Shiga toxin-producing Escherichia coli in beef

Prevalence and risk factors of Shiga toxin-producing Escherichia coli serotypes in beef at abattoirs and retail outlets in Gauteng

Industry Sector: Cattle and Small Stock

Research focus area: Red Meat Safety, Nutritional Value, Consumerism and Consumer Behaviour

Research Institute: Department of Production Animal Studies, University of Pretoria

Researcher: Prof. Peter Thompson Ph.D.

The Research Team

TitleInitialsSurnameQualification
ProfA.A.AdesiyunPh.D
DrE.MadorobaPh.D
DrL.O.OnyekaM.Sc

Year of completion : 2017

Aims of the project

  • To determine the prevalence O157 and non-O157 Shiga-toxin producing Escherichia coli (STEC) in beef abattoirs in Gauteng
  • To determine the prevalence O157 and non-O157 STEC in beef and beef products at retail outlets in Gauteng
  • To identify the important STEC serotypes present in beef and beef products in Gauteng
  • To identify risk factors for STEC contamination of carcasses and beef products in Gauteng

Executive Summary

Shiga toxin-producing Escherichia coli (STEC), particularly the O157 strains, are food-borne zoonotic pathogens of public health importance worldwide. Foods of cattle origin have been implicated in various outbreaks and epidemiological studies have revealed that cattle are major reservoirs of STEC. We conducted cross-sectional surveys from Nov 2015 to Nov 2016, to investigate the prevalence and molecular characteristics of O157 and non-O157 strains of STEC in beef and beef products in the Gauteng province of South Africa.

A total of 265 swab samples of beef carcasses from 12 abattoirs and 399 beef products from 31 retail outlets were screened for STEC using a multiplex PCR. The overall prevalence in abattoir samples was 37% (55/149) in summer and 34% (39/116) in winter. In beef products at retail outlets it was 20% (27/137) in autumn, 14% (18/130) in winter and 17% (22/132) in summer; the highest prevalence was detected in boerewors (35%) followed by mincemeat (21%). The predominant serotypes detected were O113 (19.4%) and O157 (14.9%) in beef products, and O113 (14%) from abattoirs.

Our results demonstrate that STEC is present in South African beef and beef products, and that this may pose a real food-borne disease threat. Further investigation of the epidemiology of the pathogen is required; it is proposed that this take the form of longitudinal studies to investigate the prevalence of shedding of STEC by cattle in the feedlot, following them through to the abattoir to determine factors associated with carcass contamination.

Additional Comments

As this is part of a PhD project, further molecular work is still to be done on the isolates, resulting in further planned publications. The samples also provided material for an MSc student (funded by UP research funds) to work on Salmonella contamination – these results will also be made available to RMRDSA once finalized.

Popular Article

Assessing the prevalence of shiga toxin-producing escherichia coli in beef at abattoirs and retail outlets in gauteng

Dr Lorinda Frylinck, Senior Navorser, LNR-Diere Produksie, Irene.

Introduction

The production of safe and wholesome beef and beef-derived food products is the highest priority for the beef industry in South Africa. There are potential risks associated with the possible presence of harmful pathogens in the food production chain; however, clear guidelines and regulations have been implemented to reduce these risks to a minimum and ensure a safe product for consumers. Nevertheless it remains important to continually assess these risks and to ensure effective implementation of control measures.

Shiga toxin-producing Escherichia coli (STEC) are bacteria associated with food and waterborne diseases and have been recognized as causing public health problems worldwide. The WHO Foodborne Disease Burden Epidemiology Reference Group (FERG) reported that ‘Foodborne STEC’ caused more than 1 million illnesses and 128 deaths in 2010 (8).

Of the over 470 different serotypes of STEC detected in humans, the O157:H7 serotype is the most frequently associated with large food and water-borne outbreaks (7). However, non-O157 STEC have been increasingly isolated from cases of haemorrhagic colitis (severe GIT infection and bloody diarrhoea) and as well as some fatal kidney failure (HUS; haemolytic uraemic syndrome) cases.

Although the first report of the occurrence of HUS in South Africa dated as far back as 1968 (6), the causative agent was poorly understood at that time. The first clinically proven incidence of E. coli O157:H7 in South Africa was later linked with haemorrhagic colitis (3). The importance of the pathogen in South Africa and other southern African countries has, however, been highlighted by subsequent major outbreaks of bloody diarrhoea in which E. coli O157 strains were implicated (4). Of particular interest was a study in Gauteng province in 2011, in which 7.7% of children with diarrhoea were positive for E. coli O157 (5).

Epidemiological investigations have revealed that cattle are a major reservoir of STEC. Many outbreaks of E. coli O157:H7 have been associated with beef, in particular ground beef, and analyses of some cases have identified undercooked beef as a significant risk factor. However, the fact that E. coli-associated conditions in humans, such as HUS, are not as yet notifiable in South Africa may mean that the occurrence of STEC-associated disease in humans is under-reported. In addition, given the weight of evidence from elsewhere in the world, it is possible that contamination of beef products is also a risk factor in South Africa.

Research problem and objectives

There is a dearth of current information on the frequency of occurrence of O157 and non-O157 strains of STEC, and on the risk they pose to consumers of beef products, in South Africa. Hence, the objective of this study was to determine the prevalence and characteristics of O157 and non-O157 STEC strains in beef carcass and beef products sold at retail outlets in the Gauteng province of South Africa.

Materials and Methods

During a one-year period from Nov 2015 to Nov 2016, two independent cross-sectional surveys were carried out to determine the prevalence of STEC at abattoirs as well as at retail outlets where beef-based food products are sold.

Study 1: Twelve abattoirs (six high throughput and six low throughput) were selected and each was visited during summer and winter months for sample collection. Five animals were randomly selected in each abattoir and tagged for sample collection. Firstly, samples were collected by swabbing the skin of the perineal area immediately after slaughter. Thereafter, carcass swab samples were collected from different parts of the carcass at various stages during processing, including pre-evisceration, post-evisceration, post-washing and 24 hours post-chilling.

Beef carcass sampling and processing at the abattoir

Study 2: A total of 31 retail outlets including both large supermarket chains and smaller butcheries were randomly selected. Visits were made to each of these outlets during autumn, winter and summer months of 2016 for sample collection. Sampling of five types of popular beef products (brisket, boerewors, mince, cold meat, and biltong) was done at each outlet during each visit.

Each sample was analyzed for the presence of Shiga toxin-encoding genes (stx1and stx2) using conventional multiplex PCR. All samples positive for stx genes based on PCR were screened for the following O-serotypes: O26, O91, O103, O111, O113, O145 and O157 using a multiplex PCR assay.

Results and Discussion

Overall, the prevalence of STEC in beef carcass swabs collected from 12 red meat abattoirs across Gauteng province during summer and winter months was 35.5% (94/265). The highest prevalence (50%) was detected in perineal samples, which is hardly a surprise because cattle are an established reservoir of STEC; this may therefore reflect the prevalence of the pathogen in cattle arriving at abattoirs. Transportation stress is known to increase the shedding of enteric pathogens and could therefore be a contributing factor to the observed high prevalence in perineal samples. STEC was found in 39% of both pre-evisceration and post-evisceration carcasses, while washed carcasses and 24 hour chilled carcasses had a lower prevalence of 23% and 20% respectively. Therefore, although washing of carcasses at the abattoir removed much of the STEC contamination, the fact that the bacteria were still present on the surface of some chilled carcasses is of potential food safety significance, since cuts from these carcasses end up for sale in various forms at retail outlets.

Boerewors on display in a retail outlet

Of the 399 beef products sampled from 31 retail outlets, 67 (16.8%) were contaminated by STEC strains, an observation that is of food safety significance if such products were to be improperly cooked and consumed by highly susceptible individuals.

The highest prevalence of STEC was detected in boerewors (35%), followed by minced meat (21%). Ground beef ordinarily includes meat from many carcasses; consequently a few infected livestock could potentially contaminate a great quantity of ground beef. Biltong had the lowest prevalence of contamination (5%), while brisket and cold meat had 11% and 6% respectively. These results are in contrast to a previous study in South Africa, in 2009, involving biltong, cold meat and minced meat at retail outlets, which found that 2.8% of the samples were positive for E. coli O157 (1).

The prevalence of STEC in abattoir and retail outlet samples was somewhat higher during the summer months compared to the winter months. While many factors are believed to affect the prevalence of E. coli O157:H7, only season has been consistently shown to impact the shedding of this bacterium by cattle (2), and some previous studies have also observed a higher prevalence of shedding during the warmer months than the winter months.

The serotype analysis showed that O113 was the post prevalent serotype both on beef carcasses (14%) as well as in beef-based products (19%). This observation is of particular interest considering that O113 is an emerging serotype associated with human illness and sometimes with HUS in several countries including Spain, Belgium and Australia. Serotype O113 of STEC may therefore potentially be important in human diseases in South Africa and this requires further studies. Some of the other serotypes detected  have also previously been implicated in human diseases elsewhere in the world.

Unlike in abattoir samples where the prevalence of serotype O157 was very low (1%), a higher prevalence of 15% was detected in retail meat samples. This finding may be explained in part by the fact that the current study was cross-sectional by design (giving a “snapshot” at a particular point in time) and not a longitudinal study. Therefore serotype O157-contaminated beef products may have originated from abattoirs not sampled in the current study, and the prevalence may vary greatly between places and over time. There is also a possibility that it may partially also be a result of contamination from other sources at the retail outlet level.

Mince meat on display in a retail outlet

Conclusion

This study has shown that contamination of beef products with potentially harmful bacteria can occur during different processing stages. The low numbers of reported cases of food-associated disease in South Africa suggest that the risk to consumers is low; however, it is not known whether all cases are reported, or that all cases are correctly diagnosed. Therefore, further research is needed in order better understand the dynamics of foodborne pathogens in South Africa, to accurately assess the risk they pose, and to accurately inform control measures.

It is well known that efficient implementation of control measures during slaughter and processing procedures can greatly reduce meat surface microbial contamination and ensure the safety of the final product. The South African Meat Safety Act (2000) has addressed potential risk factors by adopting several internationally recognized preventive measures such as the Hazard Analysis Critical Control Point (HACCP) system and Good Manufacturing Practices (GMP) in order to promote safe meat for consumers. The application of GMP and HACCP principles during handling and processing of products, as well as the proper cooking of meat products before consumption, will effectively reduce the threat of food borne disease.

Acknowledgments

We thank Red Meat Research and Development South Africa (RMRD SA) for funding this research and the Gauteng Department of Agriculture and Rural Development for granting us access and assistance to carry out the cross-sectional survey at the abattoirs.

References

  1. Abong’o, B.O. and Momba, M.N., 2009. Prevalence and characterization of Escherichia coli O157: H7 isolates from meat and meat products sold in Amathole District, Eastern Cape Province of South Africa. Food Microbiology, 26(2), pp.173-176.
  2. Berry, E.D. and Wells, J.E., 2010. Escherichia coli O157: H7: recent advances in research on occurrence, transmission, and control in cattle and the production environment. Advances in Food and Nutrition Research, 60, pp.67-117.
  3. Browning, N.G., Botha, J.R., Sacho, H. and Moore, P.J., 1990. Escherichia coli O157: H7 haemorrhagic colitis. Report of the first South African case. South African Journal of Surgery, 28(1), pp.28-29.
  4. Effler, E., Isaäcson, M., Arntzen, L., Heenan, R., Canter, P., Barrett, T., Lee, L., Mambo, C., Levine, W., Zaidi, A. and Griffin, P.M., 2001. Factors contributing to the emergence of Escherichia coli O157 in Africa. Emerging Infectious Diseases, 7(5), p.812.
  5. Galane, P.M. and Le Roux, M., 2001. Molecular epidemiology of Escherichia coli isolated from young South African children with diarrhoeal diseases. Journal of Health, Population and Nutrition, 19(1), pp.31-38.
  6. Kiibel, P.J., 1968. The haemolytic-uraemia syndrome: a survey in Southern Africa. South African Medical Journal, 42(27), pp.692-698.
  7. Mora, A., Herrera, A., López, C., Dahbi, G., Mamani, R., Pita, J.M., Alonso, M.P., Llovo, J., Bernárdez, M.I., Blanco, J.E. and Blanco, M., 2011. Characteristics of the Shiga-toxin-producing enteroaggregative Escherichia coli O104: H4 German outbreak strain and of STEC strains isolated in Spain. International Microbiology, 14(3), pp.121-141.
  8. WHO [World Health Organization], 2015. WHO estimates of the global burden of foodborne diseases. Available at http://apps.who.int/iris/bitstream/10665/199350/1/9789241565165_eng.pdf

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Peter Thompson onpeter.thompson@up.ac.za

Slaughter conditions to optimise chevon meat quality

Determination of slaughter conditions to optimise chevon visual and eating quality

Industry Sector: Cattle and Small Stock

Research focus area: Animal Products, Quality and Value-adding

Research Institute: Agricultural Research Council – Animal Production Institute

Researcher: Dr L Frylinck PhD

Title Initials Surname Highest Qualification
Prof PE Strydom PhD
Prof EC Webb PhD Animal Science
Dr P Pophiwa PhD Animal Science
Prof LC Hoffman PhD Animal Science
Ms GL van Wyk MSce (Registered for PhD)
Ms JD Snyman ND Histologie

Year of completion : 2018

Aims of the project

  • To determine the expression of genomic markers in five South African purebred genotypes – Bos indicus
  • To determine the optimum slaughter procedures (electrical stimulation for 15 – 60 seconds or delayed/step wise chilling – time determined by optimal pH) for carcasses from castrated and intact male goats of two breed types: Boer Goats and Indigenous Veld Goats (IVG, Eastern Cape Xhosa or Northern Cape Speckled Goats
  • To evaluate the tenderness and connective tissue characteristics in six different muscles m. longissimus thoracis et longissimus (LTL), m. semimenbranosus (SM), biceps femoris (BF), supra spinatus (SS), infra spinatus (IS) and semitendanosus (ST) in electrical stimulated carcasses of Boer Goats and IVG from castrated and intact male goats.
  • To evaluate the tenderness and calpain system ageing related characteristics in m. longissimus thoracis et lumborum (LTL) and m. semimembranosus (SM) muscles of electrical stimulated and non-stimulated carcasses of Boer Goats and IVG from castrated and intact male goats.
  • To evaluate sensory attributes and other meat quality characteristics of chevon from the respective post-slaughter treatments in m. longissimus thoracis et lumborum (LTL) and m. semimembranosus (SM) muscles of electrical stimulated and non-stimulated carcasses of the two breed types; Boer Goats and IVG from castrated and intact male goats.

Executive Summary

The demand for goat meat in South Africa is relatively low because of traditional perceptions of off smells, off flavours and expected toughness. Perceptions also exist that Indigenous Veld Goat (IGV) produce tougher meat than Boer Goat (BG) specially bred to be a meat producing breed. The name indigenous goat is perceived as being small and not suitable for meat production. It is now discovered that some Indigenous Eco-types of Southern Africa, compare well with the Boer goat in size, can also produce good meat products if good farming and rearing practices are followed. Except for the advantage to preserve the indigenous breeds for the future generations, these breeds are well adapted to the harsh climate conditions in Southern Africa and are hardy with minimum need for veterinary intervention. Production and slaughter procedures should be adapted to suit the characteristics such as the low glycolytic potential and low carcass fat of goat carcasses. There is therefore a need to optimise the pre- and post-slaughter procedures in order to optimise the chevon (goat meat) visual and eating quality.

The first aim were investigated by applying different pre- and post slaughter procedures such as castration or not, applying electrical stimulation for 20 and 30 seconds or apply stepwise chilling. The monitoring of the muscle pH and temperature, muscle energy, meat colour and tenderness showed that either controlled step wise chilling or electrical stimulation of at least 30 sec will prevent cold toughening and produce ideal conditions for the intra muscular proteolytic enzymes to optimally function. It was found that castrated animals produced more tender meat than intact carcasses, but that more subcutaneous fat were produced, which could be advantageous to its eating experience. Both breed types: Boer Goats and Indigenous Veld Goats (IVG, Eastern Cape Xhosa or Northern Cape Speckled Goats, showed the same advantage in tenderness and colour if slaughter conditions were optimised.

The intrinsic characteristics of the six different muscles m. longissimus (LTL), m. semimenbranosus (SM), biceps femoris (BF), supra spinatus (SS), infra spinatus (IS) and semitendanosus (ST) differed from each other as expected, but castrated muscles had an higher intramuscular fat content – up to 4% than that on intact carcasses – similar in both breed-types tested. Percentage collagen solubility did not differ between the different muscles, but the total collagen measured in each muscle type did differ. Thus is optimal cooking method important.

Evaluating the tenderness and calpain system ageing related characteristics in m. longissimus thoracis et lumborum (LTL) and m. semimembranosus (SM) muscles of electrical stimulated and non-stimulated carcasses of Boer Goats and IVG from castrated and intact male goats confirm that the breed types did not differ in tenderness, but castration do have an advantageous effect on tenderness. It is said for beef that sarcomere length (SL) longer than 1.7 µm does not influence tenderness, but in this project it was obvious that the shorter 1.8 µm sarcomere length compared to that of our first subproject of 2 µm could have influenced meat tenderness. It is said that the calpain system works more effectively when the SL length is longer.

Sensory panel evaluation showed attributes and other meat quality characteristics of chevon from the respective post-slaughter treatments in m. longissimus (LTL) and m. semimembranosus (SM) muscles of electrical stimulated and non-stimulated carcasses of the two breed types; Boer Goats and IVG from castrated and intact male goats. Overall it seems like the sensory panel found the LTL and SM muscles tough, although the shear force measurements was not exactly inline with their findings. As mentioned before, the slaughter conditions could have been chosen better, for instance the ES should have been 30 sec and not 20 sec. Delayed/stepwise chilling could have given better results. I do recommend though that if a future sensory panel study is being done, mutton should be included to remove the possibility of biasness. Although I have no reason to doubt the professionalism of the panel, I do think that there could be a possibility of a negativity towards goat meat.

The evaluation of carcass characteristics and yield of electrical stimulated and non-stimulated carcasses of the two breed types; Boer Goats and IVG from castrated and intact male goats (additional aim) showed more differences between castrated and non-castrated carcasses than between carcasses of the two breed types. The dressing percentages did not differ between the castrated breeds, but was a bit higher that that of the intact carcasses. There was no significant differences in the percentage meat yield between breeds, although the different commercial cuts could differ a bit in sizes, mainly because of different ratios and form of different parts of the carcass that is genotypic-ally expected.

From this project a better understanding is formed on how goat temperament differ from other farm animals, that pre and post slaughter conditions must be adapted to take their unique characteristics into account. A small change in slaughter practice can have a mayor impact on the end product. Information acquired from these and future research should be disseminated to the farmers, producers and specific abattoirs that apply to special slaughter facilities and management for chevon production.

.Development of the market for chevon in South Africa would offer more diversity of species for red meat producers and especially benefit emerging farmers who produce over 90% of the goats in South Africa. There are good indications that goats can yield chevon or kid of acceptable quality to consumers, providing that animals of an appropriate age and sex group are slaughtered, handled and fed well during production and slaughter so as to minimise stress and prevent cold shortening.

Popular Article

Karkaskwaliteit/opbrengs van intakte en gekastreerde Boerbok en groot raam inheemse eco-tiepe veld bokke (sg. Noord-Kaap Spikkel en Oos-Kaap Xhosa (IVB) bokke)

Dr Lorinda Frylinck, Senior Navorser, LNR-Diere Produksie, Irene.

Veertig gespeende Boer en veertig IVB bokkies, waarvan 20 elk gekastreerde en intakte rammetjies was is in die krale van die Landbounavorsingsraad-Diere Produksie, Irene grootgemaak. Hulle is dieselfde dieet gevoer nl. “Ram, Lam en Ooi” pille, lucerne, hooi en natuurlike gras totdat ‘n gemiddelde lewendige massas van ongeveer 35 kg bereik het (lam ouderdom/0 permanente tande). Die gekastreerde IVB bokke was gemiddeld 1 kg ligter as die ander diere.

Hierna is hul geslag en die karkasse is oornag in ‘n koelkas van ongeveer 4°C geplaas. Buiten die warm karkasmassas, is die verdere karkaskwaliteitsmetings die volgende dag geneem. Die koue karkasmassas was tussen 14 to 16 kg en daar was ‘n warm tot koue karkasmassa verskil van ongeveer 3.5%. Die uitslag % vir die gekastreerde diere (BB en IVB)(44.5%) wat ongeveer 2.5% hoër was as die van die intakte rammetjies (42.0%). Ons het die sogenaamde vyfde kwart nie bestudeer nie.

Oogspier omtrekke gemeet in mm2 van die intakte ramme van beide die BB en IVB het nie verskil nie, maar die gekastreerde BB se omtrekke was effens groter end die van die gekastreerde IVB was effens kleiner – te wagte a.g.v. die kleiner karkasse.

Die karkasse is in die volgende kommersiele snitte verdeel en geweeg: nek, dikrib, lies, blad, bors, lende, kruis, boud en skenkel. Elkeen van hierdie snitte is weer gedisekteer om die % been, % sigbare vet en % vleis vir elke snit te bepaal. Verskille wat uitgestaan het tussen die 4 proefgroepe is die hoër nek % en dikrib % van die gekastreerde BB, die groter % lies by die BB oor die algemeen en die hoër % lende en boud van die gekastreerde IVB. Die % kruis van die gekastreerde diere was effens hoër invergelyking met die intakte diere.

Uit bogenoemde massas is die % vleis, % been en % sigbare vet (insluitend onderhuidse vet) per karkas bereken. Verstaanbaar het die intakte ram karkasse ‘n 1 tot 2 % hoër been persentasie van ongeveer 23% gehad teenoor die van 22% van die gekastreerdes. Die gekastreerdes het weer ‘n 2 tot 4% hoër totale vet % gehad van 9 to 10% teenoor die van die intakte ram karkasse van 6% vir die IVB en 8% vir die BB. Teenoorgestelde is weer gevind dat intakte IVB ram karkasse ongeveer 1% meer vleis (71% van die karkasmassa) gehad het invergelyking met die van die BB karkasse (69% van die karkasmassa) en die gekastreerde IVB ‘n karkasvleis % van 67% gehad het. Niere en niervet is ook geweeg. Niervet (kg) in al die gekastreerde karkasse (0.4 kg) was meer as die van die intakte ram karkasse van ongeveer (0.3 kg).

Dit lyk asof IVB nie so goed reageer op kastrasie nie omdat hulle so effens ligter was as die ander toetsgroeps en verdere studies hieromtrent is nodig. Hierdie kan ook dalk toegeskryf word aan kompetisie vir kos en kompeterende diere behoort alpart gehou te word. Tog lyk dit nie of dit die gekastreerde Boerbokke gepla het nie. Die uitslag persentasies het egter nie verskil tussen die gekastreerde rasse nie en was effens hoër as die van die intakte ramme, hoofsaaklik a.g.v. hoër % sigbare vet.Daar was nie noemenswaardige verskille in die % vleis tussen die rasse nie. Die groottes van die verskillende snitte verskil a.g.v. bouvorm en dit is genotipies te wagte, maar oor die algemeen gee die Boerbok en groot raam Inheemse Veld Bokke dieselfde tiepe opbrengs onder dieselfde produksie omstandighede.

Hierdie studie is deel van ‘n groter projek wat deur die Rooi Vleis Navorsings en Ontwikkeling SA (verteenwoordiger van die rooivleisbedryf) en Landbounavorsingsraad befonds word.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Lorinda Frylinck on lorinda@arc.agric.za

Formal and Informal Red Meat Industry in the Western Cape

Hidden in Plain Sight: A Regional Inquiry into the Size, Scope and Socioeconomic Effects of the Western Cape’s Formal and Informal Red Meat Industries

Industry Sector: Cattle and Small Stock

Research Focus Areas: Animal Health and Welfare; Animal Products, quality and safety, nutritional value and preference; The economics of red meat consumption and production in South Africa

Research Institute: Agriculture Research Institute – Animal Production Institute

Researcher: Dr Nick Vink PhD (Agric)

Title Initials Surname Highest Qualification
Mr. Michael McCullough M

Completion Date : 2018

Aims Of The Project

  • 3.1 To determine and report the size and scope of the informal red meat I industry as well as the informal industry’s effects on food safety, animal health and l welfare and food security with an initial focus on the Western Cape.
  • 3.2 To determine and report the size and scope of the formal red meat industry as well as the formal industry’s effects on food safety, animal welfare and food security with a primary focus on the Western Cape.
  • 3.3 To create and test a combined quantitative and qualitative methodology for determining the size and scope of the red meat industry in South Africa with a primary emphasis on the informal sector, a secondary emphasis on the formal sector as well as recommendations for improving current levels of food safety, animal welfare and food security.

Executive Summary

Hidden in Plain Sight

The genesis of Hidden in Plain Sight was two previous studies of red meat marketing systems: one in a rural Municipality in the Western Cape that discovered an informal shadow industry operating alongside a formal system of abattoirs, supermarkets and independent butcheries; the other in the townships and informal settlements of Cape Town that described an informal marketing system filling a vacuum created by the abdication of the formal system of supermarkets and butcheries. Beyond the scope of both studies was an appreciation of the size and scope of the Province’s informal systems of red meat production, processing and distribution. Hidden in Plain Sight attempts to determine size and scope of the Province’s informal red meat industry, its effects on food security, food safety and animal health and welfare.

Informal livestock farmers pasturing cattle and sheep primarily on Municipal land as well as raising pigs in improvised piggeries furnish livestock for informal processing; i.e. outdoor slaughter and indoor butchery in unlicensed facilities such as home kitchens and food stands. One and two kilo ‘value packs’ are then sold from kitchen butcheries in rural communities. Braai stands located near taxi ranks, train stations and major intersection in the former townships of Khayelitsha, Gugulethu and Nyanga in the Cape Town Metropole receive live animals directly from informal producers located on City land surrounding these communities. The animals are slaughtered on the sidewalk in front the stands or in any other adjacent open space. The muscle meat is sliced into strips and braaied, the heads are skinned, split and charred and the offal is piled on the counter for sale to hawkers or take-home consumers.

The informal system exists in both urban and rural areas to serve the 2.6 million low to very low income households in the Western Cape. In addition to low incomes many urban and rural households live in virtual ‘food deserts’ where, in the absence of transportation either public or private access to food sellers is at best difficult.  Low to very low incomes and lack of access expose over half of the Province’s households to food insecurity and place 29 percent at risk of hunger.

An expectation at the inception of this study was that size and scope of the informal system although unknown would rival the formal red meat system and would be sufficient to serve a significant percentage of the Province’s food insecure households. Such was not the case. Survey data based on inspections of informal production sites throughout the Province, census  and interview data from the Veterinary Service and the Farmer Support and Development programmes of the Western Cape Department of Agriculture and interviews with Municipal Social Development officials yield numbers of informal produced livestock clearly insufficient to serve a fraction of households at risk for hunger. Three recommendations are offered to increase the capacity of the informal industry to serve food insecure households: conduct a comprehensive inventory of public land suitable for informal production; establish an informal production, processing and distribution pilot project in each District Municipality; investigate existing parallel formal – informal marketing systems in Latin America; develop a prototype two tiered regulatory frame work to facilitate food security whilst ensuring food safety.

POPULAR ARTICLE

Magazine Article

Michael McCullough

When South African consumers walk into their local supermarket to shop for beef, lamb or pork they expect a fresh, high quality, attractively packaged, nutritious product and they get it. No need to worry about the safety of the product. South African cattle, sheep and pigs are given a through once over before they set foot in an abattoir. Any animal injured, unfit or suspected of disease is promptly rejected, condemned and disposed of. It’s not a business decision, it’s the law.

What supermarket shoppers are beginning to worry about is the possibility the meat they serve their family and friends could come from terrified, abused or injured animals. They want to know that the slaughter process is humane and animal suffering is minimised. That may sound like a contradiction in terms but it’s not. Here’s why:

  • After arrival at the abattoir animals must be rested for at least an hour. The animals must calm and ready for inspection just before they are taken into the abattoir.
  • After passing single file through a narrow corridor each animal is taken individually into a slaughter room and placed in a narrow box or a harness. This happens out of sight of the other animals to reduce stress on those queued up behind.
  • The actual killing must be painless. Animals are stunned with a strong but not fatal electric shock or with a captive bolt pistol that delivers a sharp blow to the animal’s forehead.
  • While the animal is unconscious both the arteries and veins in the neck must be severed quickly and accurately. Contrary to the movies where the victim drops dead just after his throat is cut; if one or more veins or arteries are missed the animal may take from a minute to five minutes to die. If the stun wears off before enough blood is lost to shut down the brain the animal can experience pain.
  • Stunning and wielding the knife is hard, skilled and dangerous work. Humane slaughter depends on workers who are alert and careful. Tired operators may become careless or insensitive to animals’ welfare therefore abattoirs insure their operators take regular rest periods to maintain their skills.

The animal’s carcase is then moved to a high ceilinged room and hoisted head down to finish the bleeding process. The carcase is now ready for butchery. For consumers preferring kosher or halal meat the procedure is slightly different. For kosher slaughter no stunning is allowed but to minimise suffering the arteries, veins, vagus nerve, trachea and oesophagus are severed in a single quick sweep of a very sharp knife. Halal abattoirs may elect to stun the animal. Properly done the animal is unconscious in three seconds because severing the vagus nerve is like shutting down the body’s neurological switchboard.  Flip the switch and the lights go out.

One thing consumers shopping at their neighbourhood supermarket or butchery don’t want to worry about is whether the chops and steaks they’re buying are safe to eat. Should they? After all nobody wants to have friends and family or even worse, their boss over for a braai and find out later that everyone wound up at the clinic with gastric ‘distress’ or worse. This threat is all but completely short-circuited by post slaughter meat inspections, cold chain management and strict hygiene practices from the abattoir to the wholesaler to your butcher to your shopping cart.  Here’s how it works:

  • After the carcase has bled out, the head and hide are removed taking care to make sure the hair side of the hide doesn’t touch the meat. After all the animal has never seen a shower stall so the hide is pretty grimy. For this reason anything that touches the hide shouldn’t touch the meat such as dirty hands, in in the low income housing areas next to most country towns and in densely populated urban communities like Khayelitsha in Cape Town implements, dirty hands or soiled protective clothing.
  • Organs like the gut and the gall bladder contain seriously infectious bacteria like salmonella so the viscera must come out intact (the viscera is the sack that contains digestive tract). If it splits like a cheap trash bag on the way out everything you don’t want to touch the meat goes everywhere including all over the carcase. Assuming everything comes out as planned it’s time for final butchering and trimming.
  • The carcases are halved, the spines removed, all the other inedible bits and pieces as well as any contaminated meat is cut out and discarded. The carcase is washed and chilled. The slaughter and butchering processes are done.

From here to your grill is just a matter of maintaining the cold chain – keeping the carcase clean and chilled — until it passes through the wholesaler’s cold storage on its way to your neighbourhood supermarket or butchery. The carcase is then cut into meal sized portions, wrapped, marked, priced and put in the display case. Done and dusted.

Just as every coin has two sides so does every industry. The meat industry is no exception. The formal, visible side of the industry serves the middle and upper classes and the informal, mostly invisible side serves everyone else.

When low to very low income consumers shop for beef, lamb or pork do they expect high quality and fancy packaging?  Do their questions about nutrition go much further than Will it satisfy my family’s hunger or not?  Does price matter more to this consumer than where the animal came from, what condition it was in and how did it die? It’s safe to say that putting enough affordable on the table comes first; nothing else really counts.

For these reasons a growing number of South Africans are turning away from supermarkets and butcheries to buy meat produced and processed in their own communities. Why are a growing number of consumers in low income urban communities bypassing abattoirs, supermarkets and butcheries?

Until recently not much was known about the informal red meat industry in the rural Western Cape. It was not completely invisible but rather operated in the shadows just out of sight of most supermarket and butchery shoppers.  Informal stock producers who supply this industry aren’t usually landowners and depend heavily on leased Municipal property adjacent to low income housing areas and shanty towns. Cattle and sheep producers graze their animals where they can find grass and water. However pig producers must confine their animals to keep them from roaming. They build pens from scraps of lumber, sheet metal or other discarded building materials. Pig can’t be kept just anywhere; they need a source of water for mud to wallow in during the warm months (they don’t sweat enough to keep cool). The smell of an informal pig kraal is unforgettable so most are located away from housing. Although neighbours don’t seem to mind cows or sheep wandering through the community they usually draw the line at somebody else’s pig rooting in their garden.

When an informal producer is ready kill a pig, for example he or she spreads the word and takes orders. When it comes time to slaughter the producer recruits several volunteers; puts a barrel or large pot of water to boil on a wood fire and brings the pig forth. The pig is stunned by one or more blows between the eyes with a heavy hammer. A long sharp knife is inserted to the hilt just above the breastbone, twisted vigorously and pulled out. If all goes well (and it sometimes doesn’t) the pig will bleed out rapidly. Unfortunately most informal sites don’t have a convenient tree to hoist the pig so that it bleeds out completely. It’s often left on the ground to ooze blood until the time seems right to dip the carcase into the hot water to loosen the hair and underlying membrane. After the hair is scraped off down to the white skin it’s time to remove the head, the viscera and the rest of the internal organs. The pig should be hung for a day and allowed to cool. In practice this seldom happens. A carcase hanging from a tree overnight is likely to attract unwanted attention from the authorities. So the carcase is immediately butchered into saleable portions, refrigerated or frozen if possible and sold to local consumers. The helpers are usually rewarded with a share of the meat, the head and the offal.

The routine for cattle and sheep is similar except for the extra volunteers needed to handle a 150 kg cow carcase. Cow hides are removed with a knife and sheep skins are pulled off by hand. Unlike a pig no boiling and scraping is necessary.  Contamination from faeces and urine is hard to avoid and accidents often occur when the processing crew is tugging the heavy, slippery viscera out of the gut cavity not to mention the near certainty of hair and dirt on the meat. The carcase is usually rinsed with water carried to the slaughter site in buckets.  Given the rough ad tumble nature of informal slaughter it’s surprising that reported cases of food poisoning from informally sourced red meat are so rare as to be non-existent.

In Khayelitsha, a large densely populated suburb of Cape Town the informal system is not only out of the shadows it’s out loud and proud. Next to every train station, taxi rank and surrounding every major street intersection sidewalk braai stands do a thriving business in grilled beef, pork and mutton. Tens of thousands of commuters stop by these stands every day to pick up a takeaway meal on the way to and from work. Think off these stands as fast food outlets for the black urban working class. Just like the ‘McWhatevers’ in other neighbourhoods      braai stands offer accessible and  affordable (but not necessarily inexpensive) meat to consumers without the means or time to buy meat fresh, take it home, refrigerate it and cook it later. The big difference between fast food outlets in neighbourhoods like Khayelitsha and outlets other less crowded and more affluent neighbourhoods is how the meat gets there and what happens when it arrives.

Live animals are brought in from surrounding communities and slaughtered on sidewalks in front of the stands, alleys behind the stands or any unoccupied space. A source of water to rinse the carcases is strictly optional. The muscle meat is sliced into strips and immediately grilled. The heads are skinned or scraped, split and charred for serving. The offal is piled on tables and sold to customers for home consumption.

To outsiders the scene is a bloody, chaotic and cruel public health disaster. Are there issues with quality? Yes. Nutrition? Absolutely. Packaging? Of course. Safety? Afraid so. Access? No. Affordability? No. To Khayelitsha residents braai stands are a local informal industry that meets their community’s needs because the formal industry is either unwilling or unable to do so.

So which consumer model makes will prevail? The supermarket model that creates expectations of quality, safety and nutrition wrapped up in attractive packaging but comes at a high price? Or the braai stand/informal butchery next door that makes up for little or no packaging, no guarantees of quality, safety or nutrition but delivers affordable prices and accessibility?

For the foreseeable future the answer is both. Consumers who are willing and able to pay a price premium for the value added by abattoirs, wholesalers and supermarkets in exchange for guarantees of quality, safety and nutrition will continue to do so because they can. Consumers who lack the means to pay for those kinds of guarantees and who must take their chances in return for accessible and affordable meat will continue to do so because they must.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Dr Nick Vink  on nv@sun.ac.za

Chilling and electrical stimulation of beef carcasses

Effects of chilling and electrical stimulation on carcass and meat quality attributes of selected breeds of cattle with different carcass weights

Industry Sector: Cattle and Small Stock

Research Focus Area: Animal Products, Quality and Value-adding

Research Institute: University of Pretoria

Researcher: Prof Edward Webb

Title Initials Surname Highest Qualification
Mr Babatunde Agbeniga MSc
Dr P.E. Strydom PhD

Year of completion : 2018

Aims Of The Project

  • To compile a comprehensive literature review on current chilling and electrical stimulation guidelines
  • To compare chilling and electrical stimulation of selected cattle breeds of different carcass weights and to evaluate the effects of different chilling regimes and different stimulation procedures on carcass and meat quality attributes
  • To make recommendations to the meat industry on acceptable ways of chilling and stimulating carcasses in order to obtain the best quality carcasses and meat

Executive Summary

This research focused on acceptable ways of chilling and electrically stimulating beef carcasses in order to obtain the best quality meat, given the current use of growth enhancing molecules (beta-adrenergic agonists) and the current increase in carcasses size to curve the negative impact of escalating maize prices on the economics of intensive feed of beef cattle.

The literature survey suggest that low voltage electrical stimulation (LVES) is safer and more practical in South African abattoirs compared to high voltage electrical stimulation (HVES). The current research indicates that low voltage electrical stimulation has beneficial effects on meat quality of beef carcasses. Furthermore, early post mortem LVES is more beneficial compared to LVES after evisceration in terms of most meat quality attributes. Shorter duration LVES (30 sec.) was more beneficial compared to long duration LVES (60 sec.). Current chilling regimes of larger carcasses demonstrate that the effects of beta-agonist treatment on beef tenderness becomes negligible with increasing carcass size, provided that such carcasses are electrically stimulated early post mortem. Optimum carcass stimulation and chilling regimes were proposed for commercial beef abattoirs in South Africa.

OUTPUTS

Scientific publications (ISI peer reviewed)

  1. Agbeniga, B. & Webb, E.C. (2018). Influence of carcass weight on meat quality of commercial feedlot steers with similar feedlot, slaughter and post-mortem management, Food Research International, 105,793-800. (IF=3,086)
  2. Agbeniga, B. & Webb, E.C. (2018). Effects of timing and duration of low voltage electrical stimulation on selected meat quality characteristics of light and heavy bovine carcasses, Animal Production Science, (Accepted with minor changes).

Scientific conferences

  1.  B. Agbeniga, E.C. Webb, P.E. Strydom & L Frylinck, 2016. Effects of low voltage electrical stimulation and carcass size on meat tenderness and drip loss of beef carcasses treated with Zilmax®, 49th SASAS Congress, Cape Town, (Oral presentation).
  2. B. Agbeniga & E.C. Webb, 2015. Effects of duration of electrical stimulation and carcass weight on carcass pH, temperature profile and shear force of Zilmax treated beef carcasses, 48th SASAS congress, Zululand, (Oral Presentation).

Industry lectures

  1. Webb, E.C. (2016) Growth enhancers, residues and beef quality, Red Meat Abattoir Association Conference, Spier, Western Cape,
  2. Webb, E.C. (2016) Abattoir management and carcass and beef quality, Devon abattoir workshop, Protea Hotel, 22 July 2016.
  3. Webb, E.C. (2015). Factors that affect beef carcass and meat quality, North West RPO Koopmansfontein,  October 2015.
  1. Webb, E.C. (2015).Growth efficiency in feedlot cattle, Cattleman’s conference, South African Feedlot Association, March, Kiewietskroon.

Popular Article

Interactions between early and delayed electrical stimulation and carcass size on pH, temperature decline and instrumental shear force of meat samples from Zilmax treated cattle

Introduction

The time of application and duration of electrical stimulation (ES) on light and heavy carcasses from Zilmax treated animals, poses new challenges in the meat processing industry in South Africa. Owing to the use of Zilmax, larger carcasses are now being processed at abattoirs that were built to accommodate smaller carcasses. This poses new challenges in terms of optimization of conversion of muscle to meat using ES and appropriate chilling regime. In this study, the effects of early or delayed low voltage electrical stimulation (LVES) (110V) applied to light and heavy carcasses of Zilmax treated cattle were evaluated for pH and temperature decline, and the resultant effects on instrumental shear force. One hundred and forty-nine Zilmax treated cattle (mainly steers) were assigned to 10 different treatment groups according to the combination of their carcass weight (≤ 130 or ≥ 145kg side), time of stimulation (early stimulation-3 min post mortem [p.m.] or late stimulation-45 min p.m.), and the duration of stimulation (30 or 60 sec). Analysis revealed significantly (p < 0.05) faster pH decline and the lowest pH in carcasses stimulated before evisceration, at all times of measurement compared to carcasses stimulated late or non-stimulated controls. The time of ES application exerted the greatest influence on the pH profile while duration of stimulation showed minor influence. Heavy carcasses in the early stimulated groups had the lowest rigor- and ultimate pH. Regarding temperature decline, heavy carcasses had the slowest decline (p < 0.05) and the highest carcass temperatures at all times from 45 min to 24 hr p.m. Time of ES application and duration of ES did not affect carcass temperature. In terms of shear force, carcasses stimulated at 3 min p.m. had the lowest (p < 0.05) shear force at 3 and 14 days p.m. compared to carcasses stimulated at 45 min p.m. and controls respectively. Heavy carcass groups, stimulated early, with the lowest rigor and pHu, had the lowest shear force at 3 and 14 days p.m.

Effects of electrical stimulation and chilling on beef quality

Results of our recent study indicates that the time of application of electrical stimulation has an important influence on carcass pH and temperature profile, and in combination with carcass weight, has a large influence on the tenderness of beef. LVES provides a practical way to manipulate glycolysis in order to improve beef tenderness, but it appears that this treatment should be applied early post mortem in ordser to be efficient. Although there has been some suggestions to apply LVES later, the present results show that early post mortem application of LVES produced the lowest shear force, mainly due faster pH decline in combination with high initial carcass temperature.

Previous research suggested that at high muscle temperature combined with low pH, heat shortening may occur, leading to lower beef tenderness. Our results indicate that LVES treatment early post mortem passed through the heat shortening window (above 350C) within 2 hr p.m. when the pH was less than 6. This finding clearly demonstrates that the proteolytic activity was not exhausted by the low pH and elevated initial temperature in the early stimulated carcasses.

Carcass weight also played a part in improving tenderness in the early stimulated carcasses. In addition, Zilmax is known to reduce tenderness in meat but the application of ES could improve tenderness by the early activation of the calpain system. It is important to note that ES-treatment improve but do not completely overcome the negative effects of Zilmax on tenderness. In this study, we found that the combination of early ES and carcass weight significantly lowered the shear force in the heavy carcass groups. Research by Webb and Morris on Zilmax treated cattle also show that heavier carcasses from zilmax treated cattle produced more tender meat.

On the other hand, carcasses stimulated late and the controls had slower pH decline at all times of measurement, which was also reflected in lower tenderness scores at both day 3 and 14 post mortem.

Results on the duration of electrical stimulation indicates that 30 seconds or less (15 seconds) provide most beneficial results, which agrees with a number of other international studies.

Conclusion

It is concluded that the application of low voltage electrical stimulation early p.m (3 min p.m) brought about a significantly (p < 0.05) lower shear force in carcasses from Zilmax treated cattle compared to the ones stimulated late (45 min p.m) and the un-stimulated controls. Heavy carcasses (≥ 145kg) from the early stimulated groups had the lowest shear force values at 3 and 14 days p.m despite passing through the heat shortening window, which was due to lower initial pH and higher initial muscle temperature. More proteolytic activity in the heavy carcass groups was suspected to have contributed to the low shear force values and although, slightly higher (at 5.6 and 5.9 kg) when considering a threshold of 4.9 (Shorthose et al., 1986). It is acceptable, considering the fact that the animals were treated with Zilmax which is known to reduce tenderness.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Prof Edward Webb on edward.webb@up.ac.za

Effects of growth enhancers on residues in lamb

The effects of steroidal growth implants and β- adrenergic agonist, alone, or in combination on feedlot performance and residues in lamb

Industry Sector: Cattle and Small Stock

Research Focus Area: Animal Products, Quality and Value-adding

Research Institute: University of Pretoria

Researcher: Prof Edward Webb

Title Initials Surname Highest Qualification
Dr A.L. Le Riche BVSc, MScAgric
Dr Shaun Morris BVSc(Hons), MScAgric

Year of completion : 2018

Aims Of The Project

  • To investigate the feedlot performance of feedlot lambs treated with different steroidal growth implants, alone or in combination with oral beta-agonist supplementation
  • To investigate the effects of different steroidal growth implants, alone or in combination with oral beta-agonist supplementation on the residues in the meat
  • To investigate the effects of different steroidal growth implants, alone or in combination with oral beta-agonist supplementation on carcass and meat quality

Executive Summary

The objective of this study was to compare four commonly used growth promotants in a commercial sheep feedlot. The steroidal growth promotants chosen for this trial were Ralgro (zeranol), Revalor G (Rev G; TBA/oestrogen- 17β), Revalor H (Rev H; TBA/oestrogen- 17β) and Zilmax® (zilpaterol hydrochloride). The growth promotants were compared with one another and within three sex groups, namely ewe, ram and wether (castrates), to determine which molecule or combination of molecules, if any, had the most benefit and profitability when measured against a control group.  Sheep were stratified based on initial weights and then randomly allocated to treatment groups in a completely randomised control study. All sheep originated from the same farm, and they were of  similar age, breed,  transport method,  processing method, feed ( the only difference being  the groups receiving Zilmax® during the last 18 days of feeding, making provision for 3 days withdrawal), weather conditions, housing and time on feed. A time constant termination date was used in this study, in order to measure the performance of lambs in treatment groups over time.

The experimental groups were compared over a 10 weeks feeding period according to growth and carcass parameters. The parameters that were measured were gain, FI (feed intake), FCR (feed conversion ratio), ADG (average daily gain), WCM (warm carcass mass), DP (dressing percentage), CL (carcass length) and CC (carcass compactness). Data was recorded in an Excel spread sheet and checked for accuracy. The effect of experimental treatments on growth and production parameters were analysed by means of the GLM ANOVA procedure in SAS (2006). Differences between treatment means were tested at the P<0,05 level of significance by means of the Bonferroni multiple range test in order to correct for unbalanced data (missing values). Correlations between variables were analysed by means of the Pearson product moment procedure in SAS.

Data was analysed within weeks, treatment phases and also over the entire experimental period. Effects of sex, steroid treatment and beta-agonist treatment and interaction effects were calculated. In terms of growth and slaughter parameters the use of zilpaterol hydrochloride alone proved most effective. The latter can be explained by the repartitioning effect of the BAR which increased protein accretion as a result. Benefits gained were not always statistically significant, however taking cost of treatment into account, there is a definite financial significance when choosing which combination of growth promotants to use. Muscle and liver samples were collected for residue analyses, which indicated no significant residue’s in any of the treatment groups. The current data indicate that the use of the various combinations of growth enhancing molecules in sheep pose no risk to consumers in terms of the presence of residue’s, provided that the molecules are used according to prescribed procedures and dosages.

Popular Article

In South-Africa, the finishing of cattle in a feedlot, has, over many years, become part of the value chain of marketing beef. Huge amounts of money have been made available for research to find the most cost-effective ways of producing high-quality beef (Le Riche, 2014). Relatively little research in intensive, sheep production for South-African conditions has been done up to now, leaving a number of questions regarding the safe use of certain growth-promoting agents.

Traditionally sheep were finished extensively on the veld as this was thought to be the least expensive option. Alternatively, farmers bought in lambs from others who did not have enough grazing and finished them on harvested corn fields. This is also an inexpensive option as the corn residues are readily available after harvesting. These practises, however, give rise to seasonable availability of lambs with resultant huge fluctuations in lamb meat prices. Furthermore, the national sheep herd has decreased significantly over the last decade. There are various reasons for this. Drought and the resulting reduction in grazing, being one, and the substantial stock losses due to theft and predators, to name but two, being another (Mokolo, 2011).

Whenever a product is in short supply its price escalates. As a result of this, lamb has become an expensive. There, however, remains a HUGE demand for lamb as it constitutes a major source of protein for a significant part of South-Africa’s population. The constant production of lamb, that meets market specifications has thus become more and more important (Buttry & Dawson, 1990).  In an effort to make lamb more readily and constantly available and also more affordable, lamb feedlotting is increasingly being used as a method for increasing the amount of meat being produced. Due to the current high cost of feed and the labour intensive nature of such ventures, the profit margin of a sheep feedlot can be very small.

At the present time it costs about R 326.00 to FINISH a lamb that is market ready within 70 days, (cost of the lamb excluded) (Le Riche, 2014). The total profit made on such a lamb after all production costs have been deducted could be as little as R24 – 00. The profit margin is dependent on the meat: feed price ratio. In an article by Voermol Feeds (2010) it is stated that feed conversion ratio is considered to be the critical aspect of feedlot profitability. Any reduction in feed intake or increase in feed efficiency, without compromising carcass quality, is economically important (Snowder & Van Vleck, 2003)  Thus the lamb that converts feed the best (in other words the lamb that produces the most kilograms of meat, per kilogram of feed consumed), is the most profitable lamb. One could say that , an increase in profits constitutes a decrease in input cost and/or an increase in production output. Cost of feed is an important input cost, whilst growth rate and carcass composition is an important production output (Buttry & Dawson, 1990; Snowder & Van Vleck, 2003).

There is a need to balance more efficient food production, with positive public perception. This has become a great challenge. Professionals in the industry have to determine which products and methods could be optimally used to the benefit of the producers, without gaining negative opinions from the public sector and it  has to go hand in hand with maintaining a high level of consumer safety (Buttry & Dawson, 1990).

Optimal feeding conditions that promote high voluntary intake, added to a high quality, properly balanced ration should promote profitability. The high cost of quality feed is, however, making it even more important to research the responsible, effective use of different types of growth promoting agents, alone or in combination. These products have the potential to:  1) produce animals with a higher meat: fat ratio; 2) to keep the feeding time down to a minimum and to thus reduce the impact on the environment; 3) to increase the ability to supply the protein needs of an ever-growing population.

The use of BAR agonists in ruminant production animals as a growth ENHANCER has been the subject of many heated debates and much media publicity. The reason for this is the very real potential that some of these products, clenbuterol, to name one, can have serious toxic effects in human consumers. (Stachel et al., 2003). BAR agonists used as growth promoting agents, work on the basis that they reduce body fat whilst increasing muscle hypertrophy, without causing significant alterations in organ and bone mass. They are therefore also known as repartitioning agents (Beermann, 2002). Repartitioning literally means the channelling of energy away from storage cells in the liver and adipose tissue towards muscle tissue. The sensitivity of liver and adipose tissue towards insulin is lessened whilst it is increased in muscle tissue (Beermann, 2002).

Their pharmacological action leads to an improved ADG, improved gain efficiency (G: F) and increased hot carcass weight in both feedlot beef and lambs (Reeds, 1991; Beermann, 2002; Estrada-Angulo, et al., 2008). This effect is seen with no SUBSTANTIAL increase in daily DMI.

When age comparison studies were carried out, maturity of muscle tissues proved to be a critical factor with regards to efficacy .It would then make sense that receptor presence and availability would be important in the physiological effect of this drug as mature muscle would have a higher density of receptors available (Beerman, 2002). The lack of response or reduced response in young animals would also act as proof that young muscle fibres lack enough Beta adrenergic receptors, according to Beerman, (2002).

BAR agonists, such as Zilmax® function by stimulating mainly β2- AR. This causes muscle hypertrophy and hyperplasia, lipolysis and reduced lypogenesis as well as the indirect effect of lowered insulin sensitivity. According to Baxa et.al. (2010), it does have beneficial effects to treat animals with anabolic steroid implants first, following with the oral application of ZH. Cattle that received this combination treatment showed additive improvements to lean carcass mass and performance, such as ADG and FCR.

Growth enhancers such as hormonal implants and repartitioning agents such as zilpaterol hydrochloride  are used in intensive production systems to reduce the cost of production by decreasing the feeding time, improving feed conversion and increasing the carcass slaughter weight (Pritchard, 1998; Duckett & Andrae, 2001).This should prove to be true for both cattle and sheep feedlots. According to Casey (1998) the efficacy of β- receptor agonists are determined by the relationship between the chemical structure of the compound, the theoretical number of receptors that need to be stimulated to elicit a response and the resultant effect when the β2 receptors are stimulated.

Conclusions

In sheep the best reaction is obtained when Zilmax® is fed during the last 18 – 25 days (usually 21 days) of finishing, leaving time for a three day withdrawal period before slaughter. Previous studies indicate that a minimum of 48 hours was necessary in cattle, to reach a minimal residual level. It can be expected that sheep would generally react in the same manner. At present, the acceptable dosage for ruminants is 0.15 mg/kg/day which cconstitutesa dosage of 70 g/ ton of feed in sheep.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Prof Edward Webb on edward.webb@up.ac.za

Genetic study on wet carcass syndrome

Detection of quantitative trait loci affecting wet carcass syndrome in sheep

Industry Sector: Cattle and Small Stock

Research focus area: Animal Products, Quality and Value-adding

Research Institute: Agricultural Research Council – Animal Production Institute

Researcher: Lené van der Westhuizen

Title Initials Surname Highest Qualification
Prof M.D. MacNeil Ph.D.
Prof M.M. Scholtz D.Sc.
Prof M.D. MacNeil Ph.D.
Prof F.W.C. Neser Ph.D.
Prof A. Maiwashe Ph.D.
Mrs A. Theunissen M.Sc.
Ms M. le Roux M.Sc.

Year of completion : 2018

Aims of the project

  • To map quantitative trait loci affecting wet carcass syndrome.
  • To identify specific loci affecting the predisposition to wet carcass syndrome (detection of a major gene).
  • To develop a diagnostic test for the genetic predisposition to wet carcass syndrome (if a candidate gene can be identified as the cause).
  • If a major gene is not responsible for wet carcass syndrome the second phase of the project will have the aim to develop a polygenic prediction equation for the predisposition of sheep to wet carcass syndrome.

Executive Summary

Wet carcass syndrome (WCS) is a condition predominantly found in sheep, which negatively affects the quality of their carcasses. During the pre-slaughter period, the animal appears to be clinically normal, showing no symptoms of an abnormality. However, after the removal of the skin during the slaughter process the carcass appears to be “wet”. When the description and results of prior research are taken into account, no physiological, environmental or management system was conclusively identified as the causative agent of WCS. Previous research has also not considered a potential genetic basis for WCS or the potential for an interaction of genotype with the environment (stress). Furthermore, the tentative breed-specificity, i.e. Dorper sheep breed, of the condition lends some credence to a potential genetic basis for it. The current study employed the Ovine Infinium® HD SNP BeadChip and a genome-wide association analysis approach to scan the genomes of both afflicted- and unafflicted sheep in search of putative quantitative trait loci associated with the WCS phenotype. This study was not only one of the first in Southern Africa to make use of this specific BeadChip but also the first to investigate the role of genetics as a causative factor of WCS. Muscle samples from sheep carcasses (33 afflicted and 36 unafflicted) were collected from three different abattoirs.

Using a candidate gene approach it was possible to map genetic loci, RYR1 (Chromosome 14) and PRKAG3 (RN¯; Chromosome two) causative of phenotypically similar conditions such as porcine stress syndrome and red, soft and exudative meat to the ovine genome, respectively. The positions of these loci mapped to the ovine genome were not in accordance with the loci showing significant association with the WCS phenotype; and no relationship was found between single nucleotide polymorphisms located within these genes and WCS. Furthermore, along with the latter approach, the test of runs of homozygosity presented similar results as well as providing plausible evidence that WCS is not a recessive inherited condition.

To test for an association between the phenotype (WCS) and a genetic marker(s) i.e. SNPs, a case-control study design was implemented. Given the relatively small sample size of the current study, the results obtained from the GWAS attested strong evidence of at least two loci, oar3_OARX_29903534 and oar3_OARX_113973214 positioned within the non-homologous region of the X chromosome for WCS carcasses. All afflicted animals, both males and females, carried at least one allele for marker oar3_OARX_113973214, which was shown to be related to the WCS phenotype. On the contrary, some of the unafflicted animals also carried this specific allele.  Given the apparent influence of stress on WCS, these unafflicted males and females in all likelihood did not experience adequate levels of stress to manifest the condition post-slaughter. The results of the current study also indicated that WCS may possibly be a rare X-linked inherited condition, provided only female individuals are considered. Finally, two possible major loci involving two major genes, HTR2C and DMD, positioned on the non-homologous region of the X chromosome have been identified as novel positional and functional candidate genes for WCS in sheep.

Popular Article

Wet carcass syndrome (WCS) is a condition mainly found in sheep, which negatively affects the quality of their carcasses. It has been identified in both sheep and cattle breeds, however, the frequency of WCS seen in cattle is substantially less than in sheep. Despite long-standing knowledge of the condition and research, little more is known about wet carcass syndrome and its causes than when it was discovered some three decades ago. Furthermore, it is very difficult to simulate the condition and in some years it is almost absent. Possible causing factors of WCS included the over-hydration of thirsty sheep on arrival at abattoirs, transport distances to abattoirs, allergies, compulsory dip, washing of carcasses in abattoirs under high pressure, condensation in coolers and provision of feed blocks during the pre-slaughter phase.

However, research could not find any link between these factors and the occurrence of WCS. Therefore, when the description and results of prior research are taken into account, no physiological-, environmental- or management system was conclusively identified as the causative agent of WCS. However, stress experienced by the animals during the pre-slaughter period has been identified as a possible contributing factor. Some prevention strategies have been proposed, but the problem still appears from time to time and is more severe in some years.

Wet carcass syndrome is mainly observed in hairy-type Dorper sheep and crosses of Dorper with indigenous and locally developed breeds of South Africa and Namibia, and largely seen in A0 / A1 carcasses (very low fat content with poor conformation). The Dorper breed is greatest in numbers in the studied areas (geographic regions where WCS occurs most frequently) of the Northern Cape Province in South Africa and the southern part of Namibia (Kalahari dunes and sandy veld). Unofficial slaughter statistics from WCS afflicted areas, reveal that certain abattoirs have higher numbers of WCS carcasses, whereas other abattoirs in the same region will have no recorded incidences. Communication between the researcher and abattoir management exposed the seriousness of the condition to communities in the Northern Cape. The condition is found widespread across areas where the grazing quality is poor, although the quantity is often abundant. WCS is also more frequently observed during autumn and winter, especially after droughts or after periods of above-average rainfall during spring, followed by low rainfall during the rest of summer.

During the pre-slaughter period, the animal appears to be physically normal, showing no symptoms of an abnormality. However, after the removal of the skin during the slaughter process, the carcass appears to be “wet”. An uncoloured, slightly sticky, jellylike fluid gives the carcass the shiny and wet appearance. The areas most affected on the carcass are the brisket, flanks, hindquarters, sides, and back. Affected carcasses do not dry off with overnight cooling. Consequently, WCS carcasses are not accepted, with two of the main reasons being appearance and a reduced shelf life. The most sensible explanation for the reduced shelf life is that the surface of the meat is a favourable environment for the growth of microorganisms. In addition, there is an occupational hazard associated with cutting wet carcasses in that a band saw pulls more on the meat which may result in injury to the operator. These observations further illustrate how potentially detrimental WCS is to the sheep meat industry in South Africa.

Lamb producers are very concerned about this condition and are actively participating in research to find solutions for this condition and to identify management procedures to alleviate their economic losses which may collectively rise to 10’s of millions of Rand annually. Carcasses that show WCS characteristics are generally rejected at the abattoir and not sold for human consumption. Taking carcass prices and inflation into account, the loss due to WCS can be estimated at a minimum of R 45,696,774 and during 2010 alone at R 27,010,387.

The literature review showed both promising results in terms of research opportunities and the identification of possible candidate genes for WCS. These candidate genes are the ‘genetic foundation’ of animals that will produce meat with characteristics of being pale, soft and exudative- (PSE); red, soft and exudative- (RSE) and dark, firm and dry (DFD) meat. These conditions are primarily observed in pork meat, but show phenotypic (visual) characteristics that are similar to WCS. All three of these meat characteristics are ‘trigged’ by stress. PSE/RSE meat will be the result of short term stress. Short term stress will cause a rapid decline of glycogen reserves within the muscle and finally result in meat with a low pH. The opposite occurs with DFD which is caused by long term stress. Long term stress causes severe muscle glycogen depletion, which in return causes the meat to have higher than normal pH levels. Selecting swine for leaner and heavier muscles resulted in some animals having greater susceptibility to stress and meat that is of poor quality. High vulnerability to stress in pigs is today referred to as porcine stress syndrome (PSS), and results in PSE meat. PSS can be described as acute death caused by stressors such as exercise, fighting, high temperatures, birth, stocking density, loading, transport, overcrowding at abattoirs, the use of electric prodders and abuse.

From a genetics perspective, PSS and RSE are caused by mutations within genes. PSS is caused by a single recessive inherited gene, ryanodine receptor 1 (RYR1), located on Chromosome 6 of the pig genome. There have been reports on PSE meat in other species including cattle, ostriches, turkeys and chickens. The Rendement Napole (RN¯) gene is a dominant inherited gene and located on Chromosome 15 of the pig genome and will result in RSE meat. RSE meat will result in meat having a high drip loss.

The most recent research, finished in 2018, was the first study to examine the role of genetics as the leading cause of WCS. Three scientific methods were used to identify regions within the sheep genome that may contribute to the development of WCS. These methods are termed comparative genomics using candidate genes, runs of homozygosity (ROH) and a genome-wide association (GWAS) using a case-control study design. The first two methods did not provide the research team with any positive results. Firstly, the mutations within genes causing PSS and RSE in pigs most likely do not cause WCS. Secondly, an individual with identical long stretches of DNA that are inherited from parent lines is called runs of homozygosity. The research team searched for these ROH within the DNA of WCS affected carcass, but could not find any positive results.

The final phase of the study, i.e. GWAS, compared the DNA of both affected (WCS) and unaffected (normal) carcasses in search of DNA markers, named single nucleotide polymorphisms (SNPs), that might be associated with the WCS phenotype. When using the GWAS methods, an SNP will be associated with the condition when this specific genotype (genetic make-up of the animal) is more common in affected- than in unaffected carcasses. The results from this part of the study however, provided strong positive results that at least two of these DNA markers positioned on the X chromosome of the affected carcasses are most likely associated with WCS. However, these DNA markers were also found within the genotype of some of the unaffected or normal carcasses. Now to summarize the important results, some sheep carcasses that were normal also carried the same DNA markers than WCS affected carcasses. One possible explanation could be that these unaffected animals did not experience high enough levels of stress before slaughter to cause the WCS condition after slaughter.

These two DNA markers that were identified by the research team were then further linked to two genes, 5-hydroxytryptamine (serotonin) receptor 2C (HTR2C) and Duchenne muscular dystrophy (DMD). As a result, these two genes were identified as candidate genes for WCS. Many biological functions of these genes exist, however, only a few functions could be connected to WCS. Assuming the HTR2C gene causes WCS, a disruption in cell homeostasis will occur, either during before the slaughter process by means of stress and anxiety; or after the slaughter period has been completed, through the calcium ion homeostasis mechanism within the cells of WCS affected muscles. Similarly, assuming the DMD gene causes WCS, the phenotype could be due to an increase in porousness of the cell membranes of muscles causing the typical shiny wet appearance of WCS. A novel or new porcine stress syndrome was, also identified in 2012 that is also caused by the DMD gene. Both of these genes explained in more modest words, will cause the cells within the muscle to act abnormally and fluid will move out from the cells onto the surface of WCS carcasses. However, this is only a theory and the precise biological mechanism causing WCS is presently unknown.

Future studies will first attempt to determine the exact position of the DNA marker(s) that cause WCS. Under the condition that WCS is caused by a single mutation, the development of a diagnostic test to identify live carrier animals of wet carcass syndrome, will enable sheep farmers to use this information in an attempt to eradicate the condition from their flocks. It is entirely possible that previous research attempts in search of environmental ‘triggers’ or causing factors for WCS were unsuccessful due to the unintentional sampling of mostly non-genetically susceptible or normal animals. Therefore, given the information provided and modern research techniques, nutritional studies will have the ability to make use of the genetically susceptible (WCS) animals to optimistically mimic WCS.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Lené van der Westhuizen on PienaarL@arc.agric.za

Lamb and Mutton Quality Audit

South African Retail Lamb and Mutton Quality Audit

Industry Sector: Cattle and Small Stock

Research focus area: Animal Products, Quality and Value-adding

Research Institute: Agricultural Research Council – Animal Production Institute

Researcher: Dr Michelle Hope-Jones

Title Initials Surname Highest Qualificaion
Dr PE Strydom Ph.D Animal Science
Dr L Frylinck Ph.D Biochemistry
Dr SM van Heerden Ph.D Home Economics
Prof A Hugo Ph.D Biochemistry
Ms J Anderson N D Analytical Chemistry
Mrs JD Snyman N D Food Technology

Year of completion : 2018

Aims of the project

  • To measure the instrumental/physical quality (shear force tenderness, water holding capacity/cooking loss, fat and muscle colour, collagen properties, oxidative status (rancidity)), sensory qualities and chemical composition of lamb and mutton rib or loin chops (M. longissimus dorsi) from various retail outlets (including brand names and generic products).
  • To determine the reasons for variation in quality by chemical, histological, physical and biochemical tests.
  • To use the information from 3.1 and 3.2 to arrive at a list of factors needed to be addressed in research and/or technology transfer to improve meat quality in South Africa.

Executive Summary

Twenty three products (lamb loin chops) were identified and collected from the shelves of five major retail outlets and twelve smaller butcheries on 14 different dates over a three month period (n=306, certain products where not always available due to drought conditions). Products varied in type, namely Karoo lamb (lamb valued for it unique flavour attributes due to grazing on herbaceous bushes and shrubs from a particular region of South Africa), free range or feedlot. Products also varied in packaging (Modified atmospheric packaging: MAP, PVC overwrap, to openly displayed on shelves) and retailers and butcheries were spread over various socio-economic areas. Price was recorded and shear force tenderness, sensory evaluation (tenderness and flavour), colour of meat, drip loss, cooking losses and meat/fat/bone ratios were measured as properties valued by consumers at or after purchase. Physical, histological and biochemical measurements (proximate and fatty acid analyses, lipid oxidation and collagen) were performed in an attempt to explain variations in consumer related properties.

  • Both instrumental and sensory evaluations showed tenderness to be at a high level of acceptance across the board. The Karoo samples were the most tender with the free-range samples performing the worst especially with regard to sensory tenderness.
  • Karoo lamb stood out for ‘barnyard’ aroma and flavour while free-range samples stood out for ‘Karoo bossie” aroma and flavours meaning they could be distinguished from the other samples and from each other. In both cases however, the scores were of a low intensity. Karoo and free-range lamb are purchased for their distinctive flavour.
  • Karoo and free-range samples lost less drip during cooking compared to the remaining products. Thawing loss was very low in general for all the products.
  • Karoo and free-range products have more loin muscle and less fat per chop compared to feedlot products.
  • Colour of all products was at an acceptable level with no distinct pattern showing for any particular product.
  • Lipid oxidation was at a good level over all products and fatty acid profile were consistent with free-range vs. grain-fed products. This makes the lack of free-range and Karoo flavours more perplexing.
  • Karoo and free-range products were more expensive. Regarding the remaining products, price correlated more with socio-economic area and butchery vs. retailer.
  • In general lamb is of a good quality except for drip loss which needs to be attended to. This could be due to incorrect abattoir practices. Karoo lamb is sold at a premium and its lack of flavours is of concern. The consumer however is able to consistently buy tender loin chops at any retailer or butchery.

Popular Article

Quality audit of South African lamb

Dr Michelle Hope-Jones, Researcher: Animal Production Institute, Food Science and Technology Department

Meat tenderness and other quality traits are influenced by a combination of pre-harvest, slaughter and post-harvest conditions and interventions. Research addresses these factors in order to ensure maximum satisfaction for the consumer.

However, the success rate of various sectors of the meat industry to use these technologies may vary depending on factors like technical skills, knowledge, market sector, financial viability and others.

While new projects are designed to address quality challenges, very little is known about the quality of red meat offered to the consumer at various outlets. To this end, a lamb audit was recently conducted to determine the variation in quality (tenderness, colour, water properties and others) within and between different types of outlets, and also to attempt to verify the reasons for variation in quality, so that research or technology transfer can address specific problems.

Product auditing process

The fact that meat in general is distributed all over the country from various production and processing plants, and considering that much of those operations are in Gauteng and distribute to Pretoria outlets, the study was limited to proper sampling and testing within the Pretoria metropolis. All the selected outlets receive meat from different operations, assuring a reliable sample of the industry.

Twenty three products (lamb loin chops) were identified and collected (when available) from the shelves of five major retail outlets (R) and twelve smaller butcheries (B) on 14 different dates over three months (n = 306). Products varied in type, namely Karoo lamb (valued for its unique flavour attributed to grazing on herbaceous bushes and shrubs from a particular region of South Africa), as well as free range and feedlot lamb.

Products also varied in packaging, from modified atmospheric packaging (MAP), where high levels of oxygen are pumped into packages in order for the meat to maintain the desirable red colour that consumers prefer, to PVC overwrap, and also open products displayed on shelves.

Retailers and butcheries were spread over various socio-economic areas.

Evaluation of palatability

The palatability of meat is determined by a combination of tenderness, juiciness and meat flavour.

Tenderness and juiciness

Tenderness is the most variable quality characteristic and is also rated by consumers as the most important sensory attribute. Figure 1 shows that purchasing from retailers vs. butcheries had little effect on tenderness, with instrumental test levels (Warner Braztzler Shear Force, WBSF) being at an acceptable level across all outlets. All of the Karoo products however were more tender. This could be attributed to the use of growth promotants in feedlots.

There was a strong correlation between sensory tenderness (rated by a trained panel) and WBSF. Two of the Karoo products, R2K and B6K, stood out as being more tender.

One of the free range products, R5FR, performed poorly on tenderness, but also scored lower for juiciness. This could probably be attributed to abattoir processes. Increased juiciness can give the perception of a more tender product and the relationship between the two attributes can clearly be seen in the figure. Most of the products which scored low for sensory tenderness (tougher), scored low for juiciness too.

Hoewever, the overall good level of tenderness is good news for the industry.

Flavour and aroma

In the case of lamb, flavour and aroma can play as an important role as tenderness. This is especially the case when comparing free range lamb to feedlot lamb (grass-fed vs. grain-fed) and even more so with Karoo lamb, which has a very specific flavour and aroma. As expected, the three Karoo samples scored higher (a more intense aroma) for ‘barnyard’ aroma, although interestingly not for ‘Karoobossie’ aroma, except for one Karoo product. The opposite was found for the two free range products, which had higher ‘Karoobossie’ aroma when compared to the Karoo products, but did not have a strong ‘barnyard’ aroma.

When looking at the flavour profiles, once again the three Karoo samples stood out as having a stronger ‘barnyard’ flavour. The Karoo samples did not really stand out as having a ‘Karoobossie’ flavour. As Karoo lamb is sold at a premium for its very distinct flavour, it would therefore be expected for this flavour to come out strongly. Instead, the taste panel identified the Karoo samples more as grass-fed meat.

Drip loss

All the free range products, as well as two of the Karoo products (R2K and B6K), had much less drip loss (the liquid you would find in the tray) compared to the other products. In fact, they had just over half the drip loss compared to the product with the most drip (R4).

Colour

All products across the board fell into the distinctly brown category. It was expected that packaging, or whether a sample was cut fresh or was on display, would make a difference to the colour of the meat, but not even the MAP packaged samples were of a desirable colour. This is of concern as consumers rely on visual appearance at the point of purchase and meat with a bright cherry red colour is associated with freshness.

Fat and meat (muscle) ratio, price

Figure 2 shows the average percentage of fat and the actual muscle for loin chops from the various outlets. All the Karoo (K) and free range (FR) products had more meat (a greater percentage of loin muscle), compared to the other products. It was however slightly unexpected, as feedlot meat production employs beta-adrenergic agonists, which should increase muscle yield and decrease fat percentage.

However, the feedlot lamb still had a higher percentage of fat compared to Karoo and free range samples, which could overshadow the increase in muscle yield of feedlot samples. Fat percentage followed a pattern of decreasing with an increase in loin muscle, with the Karoo and free range samples having less fat.

Price

There was a strong correlation between price and loin muscle, with a larger percentage of loin muscle resulting in an increase in price.

The Karoo and free range products were markedly more expensive, except for R2K (which was sold at a lower level retail store which was more accessible to the bulk of the public). All other Karoo products were sold at butcheries in areas of increased socio-economic status. The area in which the products were bought and the type of retailer/butchery that it was bought from, seem to be more of an indicator of price, than the percentage loin muscle, with stores in higher income areas charging more.

Problems to be addressed

With lamb being an expensive product, it is good to see that the consumer can consistently buy a tender product. There are, however, a few problems which were identified.

  • Karoo lamb, which is sold as a speciality product, does not consistently stand out from other free range products.
  • Colour as a whole is also a problem, with lamb meat not having the cherry red colour that the consumer associates with freshness.
  • Generally only 50% of a loin chop consists of meat and price alone does not seem to be a very accurate indicator of how much meat the consumer will get, except for the more specialised Karoo and free range products, which have a much better meat to fat ratio.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Michelle Hope-Jones on hopejonesm@arc.agric.za

Nutrient content of lamb and mutton offal

The nutritional composition of South African lamb and mutton offal

Industry Sector: Cattle and Small Stock

Research focus area: Red Meat Safety, Nutritional Value, Consumerism and Consumer Behaviour

Research Institute: University of Pretoria

Researcher: Dr B Pretorius

Title Initials Surname Highest Qualificaion
Prof HC Schönfeldt PhD
Ms C Muller MSc
Dr N Hall PhD
Ms M Bester MSc
Ms D Human Matric

Year of completion : 2018

Aims of the project

  • To determine the nutritional composition of South African lamb and mutton offal products (raw and cooked)
  • To determine yield, retention and physical composition of the different cooked offal products to ultimately determine the edible portion of each product
  • To incorporate the nutritional composition data and physical composition data into the national food composition tables as well as the food quantities manual of the Medical Research Council

Executive Summary

Offal, also called variety meats, or organ meats or the ”fifth quarter”, have been overlooked in the past in dietary guidelines and recommendations, irrespective of their potential contribution to food and nutrition security. This study focussed on understanding the physical and nutrient composition, as well as the potential nutritional contribution of lamb and mutton offal, when used in the correct amounts, to South African diets.

Significant amounts of protein, iron and zinc (three nutrients of concern in South Africa) can be found in selected organ meats which compared favourably with beef and lamb muscle meat cuts. The most significant findings of the study were the high levels of protein (>10g/100g) found in all cooked lamb and sheep offal cuts ranging from 14.26g/g (cooked lamb intestines) to 32.6g/100g (cooked sheep kidneys). High levels of total iron were found in cooked sheep lungs (TFe=10.73mg/100g); cooked sheep spleen (TFe=11.71mg/100g); cooked sheep liver (TFe=7.95mg/100g) cooked lamb lungs (TFe=8.368mg/100g) and lamb spleen (TFe=22.83mg/100g).

Instead of simply focussing on total protein, attention has shifted to the greater importance of protein quality than actual quantity, emphasising the presence of individual amino acids in a food. Protein quality answers two important questions namely, how much protein as well as what kind of protein should be consumed. Dietary proteins are classified as either being complete or incomplete. Foods containing all essential amino acids (indispensable amino acids) are referred to as a complete protein. The sum of the essential amino acids for lamb and mutton offal varies between 4.2 g/100g and 8.1 g/100g for mutton tongue and liver respectively. The study found that South African lamb and mutton offal adheres to the requirements as set out by the Department of Health to be labelled and proclaimed as a complete, quality protein.

Offal products contribute consistently to the diet not only in terms of essential fatty acids such as linoleic acid (C18:2n-6) and arachidonic acid (C20:4 n-6), but also eicosanoic (arachidic) acid (C20) and docosanoic acid (C22) polyunsaturated fatty acids. Ruminant meats and oily fish are the only significant sources of preformed and C22 PUFA in the diet (Enser, et al., 1998; Wyness, et al., 2011). Although human beings have the metabolic capacity to synthesize C20 and C22 fatty acids from the n-6 or n-3 precursors of linoleic and α-linolenic acid respectively, an increase in the consumption of C20 and C22 n-3 polyunsaturated fatty acids could overcome the perceived imbalance in the ratio of n-6:n-3 polyunsaturated fatty acids in modern diets.

Based on the results of this study South African lamb and mutton offal cuts can be considered a good source of protein and also a nutrient dense food source. Due to the current state of nutrition in South Africa such foods are important commodities and the promotion thereof should be prioritised.

Popular Article

Nutrient density lamb and mutton offal

1Pretorius, B., 1,2Schönfeldt, H.C. and 1Bester, M.

1Department of Animal and Wildlife Sciences, Institute of Food, Nutrition and Well-being. University of Pretoria. South Africa

2Professor and Director: ARUA Centre of Excellence: Food Security

Despite economic growth, undernutrition and food insecurity remain today at unacceptably high levels, while at the same time, diet-related non-communicable diseases (cardiovascular diseases, diabetes and hypertension) have exponentially increased to become the leading cause of mortality worldwide. The situation is set to worsen dramatically in the near future as powerful drivers of change such as population growth, climate change and urbanization converge on food systems. Consumption recommendations for high quality nutrient dense foods such as animal source foods (ASFs) are of utmost importance and should be adhered to, to keep up with the specific physiological demands of each life stage. However it was found that the feasibility for nutritionally vulnerable individuals in South Africa to adhere to these recommendations seems unlikely. The dire economic climate which South Africans, particularly those of low socio economic status, currently have to face, is probably the main reason for the problem that nutritionally vulnerable individuals cannot meet the recommendations of the Food-based Dietary Guidelines for South Africans.

Offal has been overlooked in the past in dietary guidelines and recommendations, irrespective of their potential contribution to food and nutrition security in South Africa. Limited information is available on the composition of South African lamb and mutton organ meats as cooked and consumed at home. This study focussed on understanding the physical and nutrient composition, as well as the potential nutritional contribution of lamb and mutton offal, when used in the correct amounts, to South African diets.

Table 1: Moisture, fat and protein content of 100g edible portion cooked lamb & mutton offal

Lamb Mutton
n=3 Moisture Protein Fat Moisture Protein Fat
  g/100g g/100g g/100g g/100g g/100g g/100g
Intestines 55.2cd 14.3d 31.2a 48.2d 15.3d 37.9a
Lungs 74.1a 21.1bc 6.53b 71.1a 23.2bc 3.97d
Hearts 65.1b 19.3cd 13.5b 57.6bc 20.4cd 20.2c
Livers 61.2bc 23.6bc 8.39b 64.5ab 23.1bc 6.27d
Stomachs 49.6d 24.8ab 29.9a 53.1cd 17.8d 27.3bc
Kidneys 65.8b 24.4abc 12.1b 57.2bcd 32.7a 7.77e
Spleen 67.1ab 29.5a 6.62b 66.2ab 27.8ab 5.23e
Tongues 63.7b 19.2cd 16.8b 52.6cd 15.8d 33.2ab
P-value <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Note: Means with different superscripts in a column differ significantly

Table 2: Mineral content of 100g edible portion cooked lamb offal

Ca P Mg Cu Fe Zn K Na
n=3 mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g
Intestines 18.6b 124e 21.9a 0.28b 1.40c 2.60c 75.1d 38.4f
Lungs 8.90b 271c 22.2a 0.46b 8.37b 2.59c 298b 160b
Hearts 5.12b 195d 29.0a 0.49b 3.84bc 2.49c 261b 101cd
Livers 5.03b 423a 28.3a 17.9a 6.07bc 4.17a 315b 70.8e
Stomachs 52.7a 170de 25.3a 0.40b 4.85bc 3.90a 155c 79.5de
Kidneys 9.38b 330b 30.6a 0.53b 4.44bc 3.67a 310b 234a
Spleen 7.57b 406a 30.8a 0.29b 22.8a 3.60ab 409a 112c
Tongues 17.7b 184d 24.0a 0.31b 1.50bc 2.83ab 276b 102cd
P-value <0.001 <0.001 0.132 <0.001 <0.001 <0.001 <0.001 <0.001

Note: Means with different superscripts in a column differ significantly

Table 3: Mineral content of 100g edible portion cooked mutton offal

Ca P Mg Cu Fe Zn K Na
n=3 mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g
Intestines 16.6b 112c 16.9cd 0.15b 1.69e 2.55b 50.2d 29.5e
Lungs 11.0bc 250b 19.4bcd 0.41b 10.7a 2.62b 285bc 190b
Hearts 6.00c 223b 24.8ab 0.65b 4.54c 2.74b 275bc 97.5cd
Livers 5.60c 399a 26.2ab 31.87a 7.96b 4.38a 326bc 78.7cde
Stomachs 24.6a 112c 15.9d 0.25b 2.70de 3.37ab 104d 58.7de
Kidneys 15.6b 400a 30.7a 0.56b 4.34cd 4.49a 279bc 270a
Spleen 6.00c 414a 31.4a 0.15b 11.7a 3.61ab 472a 112cd
Tongues 8.70c 142c 23.3bc 0.20b 1.81e 2.91b 235c 122c
P-value <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Note: Means with different superscripts in a column differ significantly

Table 4: Contribution to NRV’s and nutrient content claims per 90g cooked offal meat
INRV according to the Foodstuffs, Cosmetics and Disinfectants act (DOH, 2014)

Protein Calcium Phosphorus Magnesium Iron Manganese Zinc Potassium Sodium
NRVI 56g 1300mg 1250mg 365mg 13mg 2.3mg 10mg 4700mg 2000mg
Mutton % of NRV per 90g servingII III
Intestines 25IV 11 8 0 12 0 23 IV 1 1
Lungs 37v 7 18 IV 0 74 VI 0 24 IV 5 9
Hearts 33 0 16 IV 0 31v 0 25 IV 5 4
Livers 37v 0 29 IV 0 55v 0 39v 6 4
Stomachs 29 IV 2 8 0 19 IV 0 30v 2 3
Kidneys 52v 1 29 IV 0 30v 0 40v 5 12
Spleen 45v 0 30v 0 81 VI 0 32v 9 5
Tongues 25IV 1 10 0 13 0 26 IV 4 5
Lamb % of NRV per 90g servingII III
Intestines 23IV 1 9 0 10 0 23 IV 1 2
Lungs 34v 1 19 IV 0 58v 0 23 IV 6 7
Hearts 31v 0 14 0 27 IV 2 22 IV 5 5
Livers 38v 0 30v 0 42v 10 38v 6 3
Stomachs 40v 4 12 0 34v 8 35v 3 4
Kidneys 39v 1 24 IV 0 31v 2 33v 6 11
Spleen 47v 1 29 IV 0 158VI 0 32v 8 5
Tongues 31v 1 13 0 10 0 25 IV 5 5

 II 90g is the prescribed portion size for lean meat according to the Food-based dietary guidelines for South Africans (Schönfeldt, Pretorius, & Hall, 2013)

III Values do not take bioavailability into account

IV ” Source of” as per the Foodstuffs, Cosmetics and Disinfectants act (DOH,2014)

v “” High in” as per the Foodstuffs, Cosmetics and Disinfectants act (DOH,2014)

VI ” Excellent source” as per the Foodstuffs, Cosmetics and Disinfectants act (DOH,2014)

South African lamb and mutton offal can be considered a good source of protein and a nutrient dense food. In the case of protein, zinc and iron, three nutrients of concern in South Africa, all lamb and mutton organ meats were at least a source of two out of these three nutrients with lamb and mutton spleens and lamb and mutton lungs being excellent sources of protein. In view of the current disturbing state of nutrition in South Africa, as well as efforts to reduce food waste, lamb and mutton organ meats were found to be important food commodities and it was suggested that the promotion of offal should be prioritised.

Quantitative food data goes hand in hand with the nutrient composition tables used in a given country, because it provides supporting information on the food items included in the nutrient composition tables. Good quality nutrient composition and quantitative food data play an integral role in reporting the nutrient intake of a population, as well as interpreting results of certain epidemiological research. A new set of quantitative data on the nutrient and physical composition (meat, bone and fat fractions) and yield of different offal cuts were generated to assist researchers in collecting more precise, product specific data to measure nutrient in South African food consumption studies.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Beulah Pretorius on beulah.pretorius@up.ac.za

Improved red meat marketing in South Africa

Improving the effectiveness of the red meat industry in meeting the needs of the modern consumer within South Africa as a developing country with socio-economic diversity

Industry Sector: Cattle and Small Stock

Research focus area: 

  • Red Meat Safety, Nutritional Value, Consumerism and Consumer Behaviour
  • The economics of red meat consumption and production in South Africa

Research Institute: Bureau for food and agricultural policy (BFAP)

Researcher: Mrs Hester Vermeulen

Research Team

Title Initials Surname Highest Qualification
Prof Ferdi Meyer PhD Agricultural Economics
Prof HC Schönfeldt PhD
Dr B Pretorius PhD

Completion: 2017

Aims of the project

  • Improving the effectiveness of the South African red meat industry in meeting the needs of the socio-economical diverse consumer market in South Africa through the development of scientifically based recommendations to guide policy development and product development / improvement.
  • To identify and characterize consumer market segments among low-, middle- and high LSM consumers in South Africa based on consumers red meat perceptions and behavior – considering a variety of species and meat cuts guided by data availability.
  • To develop scientifically based recommendations for the promotion of red meat in South Africa through appropriate marketing messages delivered through suitable communication channels to maintain and / or improve consumers’ perceptions and acceptance of red meat – considering a variety of species and meat cuts guided by data availability.
  • To engage in GAP analysis in order to identify the discrepancies between the actual current characteristics and ideal characteristics (demanded by consumers) of the red meat product offering on South African retail shelves – considering beef and mutton/lamb and a selection of fresh meat cuts guided by data availability.

Executive Summary

Meat purchasing and preparation behaviour:

  • Meat purchasing roles:
    • Marketing information on red meat should have a strong focus on adult women (‘wife’ or head female in households) as the primary red meat purchasers, but still keeping in mind that all age and genders groups within the household could influence her red meat purchase decision. Given the increased role of the husband / head male on meat purchasing during weekends and when selecting meat to entertain guests, red meat information related to these more social settings should be targeted at both male and female adults.
  • Factors considered when purchasing red meat:
    • Across the socio-economic spectrum, for both raw beef and raw mutton/lamb the following factors were important to consumers when making a purchase – and are thus important factors to focus on in terms of red meat production and marketing, no matter which socio-economics group is targeted:
      • Affordability: Price.
      • Appearance: General appearance, colour of meat, colour of fat.
      • Food safety: Food safety in general, expiry date, clean meat (no blood).
      • Quality: Quality guarantee, fresh, fresh not frozen.
      • Sensory acceptability: Tasty, tender, juicy, eaten by all in household.
      • Convenience: Convenience in general, preparation time.
      • Fat: Fat-to-meat ratio, low fat / lean meat.
      • Store where meat is purchased.
    • Among the low-income sample value-for-money considerations such as bone-to-meat ratio, amount of meat per packet and packaging size were also important. The importance of branding and nutritional value increased towards the middle- and high-income samples.
  • Meal planning:
    • As consumers across the socio-economic spectrum usually choose the meat for the meal first and then the other dishes it is critical to ensure that red meat is positioned as a popular ‘spontaneous’ choice in consumers’ minds.
    • Consumer education on red meat meal preparation ideas should rely on multiple sources with the dominant sources being ‘social’ sources and radio for the low-income sample, and recipes, ‘social’ sources (such as friends, mother), television and magazines for the middle- and high-income samples.
  • Red meat preparation and cooking:
    • For beef the most popular cooking methods were stewing, frying and braai. For the low-income group stove-top boiling was also prominent, while roasting and grilling popular cooking methods among middle-income and high-income consumers.
    • When preparing mutton/lamb low-income consumers used frying, boiling and braai, while middle-income consumers mainly used casserole, potjie, braai, roasting and stewing (in order of importance). High income consumers used stewing, braai, roasting, frying and grilling (in order of importance) for lamb/mutton.
    • Among middle- and high-income consumers the time allocated to meat preparation increased during weekends and even more so when entertaining guests. Thus, when targeting these segments with meat preparation information and recipes for more ‘social’ meals, more complex and longer preparation time can be used. However, during the week these consumers want meat options that are easy and fast to prepare.

Meat consumption behaviour:

  • Perceived importance of protein food intake:
    • Considering the statement: ‘It is important to eat animal protein foods daily’, the majority of high- and middle-income consumers were in agreement (96% of high-income sample versus 86% of middle-income sample).
    • Considering the statement: ‘It is important to eat red meat 3 to 4 times per week’, a smaller share of high- and middle-income consumers were in agreement (65% of high-income sample versus 39% of middle-income sample).
    • There seems to be a gap for consumer education particularly among middle- and high-income consumers on the recommended healthy intake of red meat and the health benefits associated with red meat.
  • Protein food intake:
    • The animal protein food options consumed in largest quantities were (in order of importance):
      • Low-income consumers: Chicken, eggs, beef, chicken offal, fish and beef.
      • Middle-income consumers: Chicken, eggs, fish and beef.
      • High-income consumers: Chicken, beef, eggs and fish.
    • The most frequently consumed animal protein food options were (in order of importance):
      • Low-income consumers: Eggs, chicken offal, chicken meat, canned fish, polony / viennas, boerewors, beef liver and stewing beef with bone.
      • Middle-income consumers: Chicken, eggs, beef mince, fish, boerewors, beef (stewing, steak, roast, sausage), cold meats, mutton/lamb (chops, stew).
      • High-income consumers: Chicken, eggs, beef (mince, stew, steak, sausage), cold meats, pork, fish, mutton/lamb.
    • The results in terms of the most popular meat option and red meat cuts could provide the red meat industry with important market intelligence in terms of actions to ensure the continued popularity of prominent cuts as well as the identification of ‘underutilised’ cuts. Furthermore, the meat intake data presented in this report could be very valuable from a food intake / nutritional / food security perspective, as it provides more detailed information on the meat consumption patterns of South African consumers.
  • Changes in red meat intake over time:
    • A significantly larger share of the low-, middle- and high-income consumers indicated that they consumed less red meat than 2 years before the survey (Beef: 87% of low-income consumers, 75% of middle-income consumers and 80% of high-income consumers; Mutton/lamb: 72% of low-income consumers, 85% of middle-income consumers and 88% of high-income consumers). These shares are significantly higher than previous research (2003) where 45% of the total sample reported reduced beef intake. Red meat was mainly replaced by chicken meat and some fish. The main reasons for reduced red meat intake (similar to past studies) were high prices (expensive) and some health concerns.
  • Popularity of red meat among household members:
    • Red meat was generally more popular among adult consumers than among children and teenagers. There might be a growth opportunity for the red meat industry if red meat could be made more appealing to younger consumers, e.g. through innovative product formats, child-friendly recipes and consumer health education.

Meat perceptions:

  • About a third of the low-income consumers remove all visible fat before cooking, while about 15% remove some visible fat before cooking beef and chicken. The serving of meat ‘pan drippings’ originating from the cooked meat applied to about half of the low-income consumers.

Red meat safety:

  • When defining red meat safety consumers across the socio-economic spectrum focused on clean meat, clean purchase environment, meat colour, freshness, grading, expiry date, healthiness and good quality.
  • Considering the relationship between red meat quality and red meat safety a large share of respondents perceived the terms to the basically the same and being equally important when purchasing red meat.
  • The large majority of all respondents (78% to 98% of the various socio-economic sub-samples) perceived food safety as an important factor considered when purchasing red meat. However, only about 13% of the low-income consumers and about a third of the middle- and high-income consumers had red meat safety concerns. It could be argued that consumers ‘control’ for food safety by carefully selecting their red meat purchase outlets. It is also important to note that food safety seems to be a ‘non-negotiable’ attribute to consumers – it has to be in place, implying a responsibility on the red meat industry and retailers to ensure the safety of red meat sold to South African consumers.
  • The low- and middle-income consumers were most concerned about the safety of beef, followed by chicken, while the high-income consumers were most concerned about safety of chicken and beef.
  • The most trusted purchase outlets for red meat are dominated by specific trusted butchery shops and formal major retail chain store, while the most risky purchase outlets for red meat are dominated by hawkers / street vendors, spaza shops, small independent retailers, certain butchery shops and certain chain retailers.

Food-away-from-home:

  • The purchasing frequency of take-away meals differed significantly between income groups, with weekly take-away food purchasing observed for 5% of low-income consumers, 19% of middle-income consumers and 29% of high-income consumers. The results confirmed the dominance of chicken as a popular meat choice among all socio-economic groups, even though beef is also a prominent choice among high-income consumers when purchasing take-away meals.
  • The purchasing frequency of restaurant meals differed significantly between income groups, with weekly restaurant food purchasing observed for 6% of low-income consumers, 11% of middle-income consumers and 9% of high-income consumers. In terms of meat types chicken is the dominant option purchased from restaurants by the middle-income group, even though the popularity gap between chicken and beef is less prominent than for take-away meals. Among the high-income sample beef is the most popular option, followed by fish/seafood.
  • Challenges facing the red meat industry includes increasing the appeal of beef within take-away- and restaurant meals, particularly among the middle-income group; and increasing the appeal of mutton/lamb within restaurant meals, among middle- and high-income consumers.

Red meat information sources:

  • The most highly used and trusted red meat information sources for the particular socio-economic sub-segment were the following:
  • Low-income consumers: TV, radio, advertising, doctors, newspapers;
  • Middle-income consumers: TV, family, friends, doctors, recipe books, radio, food labels;
  • High-income consumers: Family, friends, food labels, recipe books, butcheries, doctors, dieticians.
  • Doctors are among top 10 most used and most trusted meat info sources for all income sub-segments;
  • TV and radio are the top 10 most used and most trusted meat info sources for middle income and low income sub-segments. However, the particular channels / stations will vary between LSM groups.
  • Family and friends (possibly linked with social media), recipe books and food labels are among the top 10 most used and most trusted meat info sources for middle income and high income sub-segments.
  • Advertising and newspapers are among the top 10 most used and most trusted meat info sources for low income sub-segment only, while butcheries and dieticians among top 10 most used and most trusted meat info sources for high income sub-segment only.

Red meat classification:

  • Among low LSM consumers there is a very limited understanding and attention given to red meat classification. Even though middle LSM and high LSM consumers also have a limited understanding of red meat classification, around half of these sampled consumers check the grading / classification mark sometimes or often when buying beef or mutton/lamb.
  • The association of red meat classification with meat quality and safety was limited. Even though many respondents did not mention red meat classification / grading directly when defining red meat quality and safety, many aspects related to it was mentioned such as freshness, meat colour, appearance, smell, tenderness, taste and leanness.
  • Among an extensive range of red meat decision factors ‘grading / classification’ was not among the top 20 most important factors. However, many aspects related to red meat grading / classification was important such as appearance, taste, flavour, quality guarantee, meat colour, fat content, juiciness and tenderness.
  • It is interesting to note that the results presented on the radar plots in terms of consumers’ red meat decision factors, the place of purchase is a stronger quality cue to consumers than the certification marks on the meat. This is an important observation and should be further investigated.

Credence / intangible red meat attributes:

  • The most popular intangible attributes among the middle-income consumers were (in order of importance) (% of sample perceiving attribute as ‘very important’ indicated in brackets): environmentally friendly production (54%), free range (49%), no growth hormones given to animals (44%), animal friendly production (44%), breed of animal (43%) and no GM feed given to animals (43%). The question however arises whether these consumers have the purchasing power to afford the price premiums associated with these attributes.
  • The most popular intangible attributes among the high-income consumers were (in order of importance) (% of sample perceiving attribute as ‘very important’ indicated in brackets): no growth hormones given to animals (56%), no GM feed given to animals (49%), environmentally friendly production (48%), animal friendly production (39%) and free range (36%).
  • In terms of demographic variables (LSM group, gender, age, ethnicity, marital status, household income level and education level), within the middle- and high-income samples, the segments deeming intangible attributes as ‘very important’ did not differ significantly from the alternative segments.
  • The most highly used and highly trusted red meat information sources among the middle- and high-income consumer samples for consumers who perceived at least four or more of the intangible attributes as ‘very important’ were TV, family friends, advertising, food labels, recipe books, newspapers, butchers, radio, magazines, retailers, dieticians, food industry, public health recommendations, doctors, farmers and consumer organisations. These results (presented for each intangible attribute separate in the particular chapter) present marketers of red meat with a valuable overview of the marketing channels to use when marketing red meat products with particular intangible product traits.

Market segmentation for specific beef and mutton/lamb cuts:

  • Market segmentation for individual red meat cuts were based on respondents’ consumption frequency for the various cuts, considered at four consumption frequency levels: weekly (‘weeklies’), 1 to 3 times per month (‘monthlies’), occasionally (‘occasionals’) and never (‘non-users’).
  • Among the low-income consumers the most popular red meat cuts (with the highest shares of ‘Weeklies’ and ‘Monthlies’ combined) were: offal in general (78.8%), beef stew (67.1%), beef mince (46.7%) and beef steak (43.0%). Offal was significantly more important among the low-income sample compared to the wealthier samples.
  • Among the middle-income consumers the most popular red meat cuts (with the highest shares of ‘Weeklies’ and ‘Monthlies’ combined) were: beef mince (89.6%), beef stew (84.2%), beef steak (59.1%), beef roast (48.5%), mutton/lamb chops (39.7%), offal in general (32.8%) and mutton/lamb roast (31.6%).
  • Among the high-income consumers the most popular red meat cuts (with the highest shares of ‘Weeklies’ and ‘Monthlies’ combined) were: beef mince (95.1%), beef stew (83.8%), beef steak (79.9%), mutton/lamb chops (69.4%), beef roast (60.5%), mutton/lamb stew (56.0%) and mutton/lamb roast (28.7%).
  • In terms of demographic variables the results indicated that consumers’ consumption frequency of red meat cuts did not generally differ in terms of household’s size and income as well as the respondent’s gender, age and ethnic group. However, the more aggregated wealth level of consumers (in other words whether they were among the low-, middle- or high-income samples) did make a differences in terms of their red meat intake frequency – with more frequent intake generally associated with higher income brackets.
  • In terms of typical weekly expenditure on particular red meat cuts, more regular low-income consumers revealed a tendency to spend more on red meat considering the segments for beef mince and beef steak. More regular middle-income consumers revealed a tendency to spend more on beef mince, beef steak, beef stew, beef roast, mutton/lamb chops and mutton/lamb roast.
  • In terms of typical quantity of raw red meat consumed per week, more regular middle-income consumers revealed a tendency to consume a larger weekly quantity of beef mince, mutton/lamb chops, mutton/lamb roast, mutton/lamb stew. More regular low-income consumer revealed a tendency to consume a larger weekly quantity of beef offal and mutton/lamb offal. The lack of significant differences for the other cuts within the three main samples once again imply that since more regular consumers and less regular consumers of red meat consume a similar quantity of red meat per week, the more regular segments could be consuming smaller quantities per (more regular) eating occasion.
  • For the various red meat cuts, considered for the low-, middle- and high-income samples, this section also presented information on consumers’ perceptions regarding beef and mutton/lamb, purchase factors, and best information sources to use to provide consumers with red meat information.
  • Across red meat cuts and socio-economic samples, consumers were very consistent in terms of their requirements for red meat labels, with preferences for detailed information and reliable information, date information (use-by date, sell-by date, last day of processing) and information pertaining to production processes (particularly in terms of the use of antibiotics / hormones and also free range in some cases).

Red meat labelling – What do consumers want and what do they see on labels?

  • The red meat labelling aspects that are highly desired by consumers and were widely observed on fresh red meat labels were: price, quality guaranteed, sell-by date and brand.
  • Despite being very important to consumers, labelling information relating to fat content, nutritional value and classification were not commonly observed on the fresh red meat labels.
  • In terms of date information packaging date, sell-by date and expiry date were the most commonly found on fresh red meat labels.

POPULAR ARTICLE

Red meat consumer education – key messages and marketing channels focusing on beef

Mrs Hester Vermeulen, Bureau for Food and Agricultural Policy

Prof Hettie Schönfeldt, University of Pretoria

Dr Beulah Pretorius, University of Pretoria

 Acknowledgements: Project funding provided by Red Meat Research and Development SA (RMRD-SA)

PLEASE NOTE:

‘Background’ pictures /photos of the following could work well with this article:

  • Consumer buying beef in a shop
  • Consumer preparing beef in kitchen
  • Eating beef in a restaurant
  • Braai with beef on the grid
  • Example of a nutritional label from a beef product

Introduction:

The share of South African adults within the various socio-economic sub-groups changed significantly from 2005 to 2015, with the marginalised consumers decreasing by 52%, the middle class increasing by 50% and the more affluent consumer group increasing by 32%. The future of the South African red meat industry relies on an industry that are profitable and able to adapt to changes in consumer demand, the production environment and sustainability.

In 2012 the South African red meat industry commissioned a comprehensive consumer study to investigate the red meat behaviour and perceptions of the South African low-, middle- and high-income consumers in Gauteng amongst 586 consumers. The study sample was designed to reflect the income, ethnic and age groups of the South African population. The focus of this article is specifically on the identification of key marketing messages and marketing channels for red meat marketing.

How do South African consumers perceive beef?

Respondents were asked to indicate their level of agreement with a series of statements involving potential attributes of beef, pertaining to health / nutrition, affordability, product usage, product procurement, preparation, sensory quality and potential negative aspects.

Considering the positive perceptions of consumers regarding beef, there is significant overlap between income groups involving the following:

  • Product procurement: Beef is easy to obtain.
  • Product usage: Consumers know how to prepare beef, it is easy to cook the meat, it is versatile, good for entertaining and ideal for braai.
  • Sensory quality: Beef is tasty and tender and it does not smell bad.
  • Health / nutrition: Beef is a source of good quality protein and iron, it is nutritious and helps the body grow.
  • Product origin: Beef is locally produced and not imported.

The aspects which dominated the ‘positive’ set for beef of all income groups were: versatile, tasty, know how to prepare it, easy to obtain, good for entertaining, easy to cook and good quality protein source. Popularity when eating in a restaurant was also applicable to the middle-class and more affluent group, with higher importance in the latter group. Furthermore the more affluent group was also positive about further health / nutrition aspects (such as ‘healthy’ and ‘contains iron’), shelf life at home (‘does not go off fast’) and affordability (‘value for money’ and ‘not a luxury’).

Among marginalised and middle-class groups the major concerns (i.e. negative perceptions) focused on beef being expensive, having long cooking times and could cause health problems. Among the more affluent consumers the major beef concerns focused on specific health aspects (high in cholesterol, could cause health problems, can make me ill) and long cooking times required. A significantly larger share of the low-income sample was negative towards beef in terms of the following beef aspects: expensive, long cooking times required, can make me ill, high in fat and ‘not good for the heart’. In general a higher share of the marginalised group was in agreement with these negative aspects pertaining to beef, in contrast to a lower share of the more affluent consumers. As would be expected, consumers’ concerns regarding the affordability of beef decreased as income levels increased.

How do these perceptions translate into marketing messages to promote SA beef?

To enhance beef consumption in the South African context key marketing messages needs to take these observed perceptions into account. Beef product attributes and perceptions and translated marketing messages are proposed in

Table 1.

Product usage and preparation:

Across the socio-economic spectrum consumers were very positive about beef being versatile, easy to cook, knowing how to prepare it, good for entertaining and ideal for braai. The industry could invest or continue to invest in product- and recipe development to ensure that beef remains versatile, familiar, easy-to-cook, ‘trendy’ and a number one choice when entertaining of having a braai. Innovative ways to reduce beef cooking time for consumers with limited time should also be investigated, as well as innovative and tasty recipes to ‘stretch’ beef in dishes. However, it is important to consider the varying life styles, preferences and budgets of the socio-economic sub-groups in the process.

Sensory appeal:

All consumer segments were very positive about beef being tasty and not smelling bad. The middle-class was more positive about the tenderness of beef, even though tenderness was among the positive perceptions of all sub-groups. Sensory appeal is a critical product attribute for beef, even more so given its price premium about chicken meat. Production and product handling practices should continuously be improved, based on sound scientific research, to ensure ‘better beef’ – satisfying the sensory enjoyment needs of consumers of all income groups (e.g. in terms of taste, tenderness, smell and visual appeal).

Health – food safety:

Only the more affluent group was very positive about beef not spoiling fast at home. The lack of cold-storage facilities in the homes of lower-income consumers could contribute to this observation. However, there seems to be a need for consumer education on safe meat handling practices, particularly among the marginalised and middle-class groups.

Health – nutritional value:

All consumers perceived beef as being nutritious, a good quality protein source, helps the body grow and being a source of iron. Only the more affluent group were very positive about beef being ‘healthy’. The research results suggest that consumers (across the socio-economic spectrum) need to be educated on the nutritional value of beef, pertaining to various aspects such as macro-nutrients (i.e. protein, fat) and micro-nutrients (i.e. vitamins and minerals). However, it should be kept in mind that the complexity of nutritional information communicated to consumers should be tailored to their typical educations levels.

Health – fat & cholesterol:

Over the last decade or two a growing body of scientific publications confirm the trend of consumers moving towards leaner red meat cuts. In this study consumers were concerned about beef in terms of fattiness, being high in cholesterol and the intake of beef linked to heart disease – with the marginalised group being particularly negative. Addressing consumers’ red meat fattiness concerns is critical, even more so in the light of the rising prevalence of overweight and obesity in South Africa. Corrective actions could include the following:

  • Presenting consumers with leaner beef cuts (e.g. through animal production processes and / or trimming of fat from beef cuts before sale).
  • Consumer education on the tasty preparation of leaner beef cuts (including aspects such as fat trimming at home and avoiding excessive fat intake through actions such as serving pan-drippings with meat with a high fat content).
  • Presenting consumers with a balanced and scientifically sound view on issues pertaining to beef fattiness, cholesterol and heart disease.

Product origin:

All consumers were positive that the beef they buy is usually local meat, suggesting some loyalty to locally produced beef. This is even more important if the large quantity of chicken being imported into the country is considered. The industry could do much more to communicate the origin of beef to consumers and extract some value from consumers’ loyalty towards locally produced meat.

Table 1: Proposed key marketing messages translated from consumers’ perceptions regarding beef meat

Product attributes and perceptions Key marketing strategies and messages
Product usage and preparation:
•     Versatile

•     Easy to cook

•     Knowing how to prepare

•     Good for entertaining

•     Ideal for braai

ü Continuous product- and recipe development to ensure that beef remains versatile, familiar, easy-to-cook, ‘trendy’ and a number one choice when entertaining or having a braai

ü Tasty recipes to ‘stretch’ beef in dishes

ü Innovative ways to reduce beef cooking time

Sensory appeal:
•     Beef is tasty

•     Beef is tender

•     Does not smell bad

ü Improved production and product handling practices based on sound scientific research, to ensure ‘better beef’
Health – food safety:
•     Beef do / does not spoil fast ü Consumer education on safe meat handling practices
Health – nutritional value:
•     Beef is nutritious

•     Beef is a good quality protein source

•     Beef helps the body grow

•     Beef is a source of iron

•     Beef is too fatty

•     Beef is high in cholesterol

•     Eating beef causes heart disease

ü Consumer relevant education on the nutritional value of beef, pertaining to various aspects such as macro-nutrients (i.e. protein, fat) and micro-nutrients (i.e. vitamins and minerals).

ü Leaner beef cuts

ü Consumer education on the tasty preparation of leaner beef cuts

ü Presenting consumers with balanced and scientifically sound messages on issues pertaining to beef fattiness, cholesterol and heart disease

Product origin & Affordability:
•     Beef is locally produced

•     Expensive

ü Communicate the origin of beef to consumers

ü Address affordability issues through promoting it as an ‘essential luxury’ or by providing more affordable meat cuts to the consumer

Which communication channels are most suitable to communicate these marketing messages to SA consumers?

Being presented with a list of potential red meat information sources, consumers were asked to evaluate the usage and trust of these sources. Table 2 summarised the most used and trusted information sources amongst the different consumer groups to use in marketing strategies. However, given the diversity of the market the specific channels (e.g. which television channels or which newspapers) as well as the complexity of marketing messages has to be tailored to the behaviour and education levels of the targeted consumers.

Table 2: Highly used and highly trusted red meat information sources (Source: Survey data) 

Category: Information source: Marginalised

group:

Middle-class

group:

More affluent

group:

Printed information sources: Magazines

 

ü
Newspapers

 

ü û
Recipe books

 

ü
Food labels

 

ü
Advertisements

 

ü ü
Medical information sources: Doctors

 

Dieticians

 

û ü ü
Retail information sources: Retail stores

 

ü ü û
Butchers

 

ü ü
Social information sources: Family

 

ü
Friends

 

û
Broadcasting information sources: Television

 

Radio

 

û
Other information sources: Public health recommendations

 

ü ü ü
The food industry

 

û û ü

(NOTES: : Indicates red meat information sources that dominates for the particular sub-group)

Conclusions and implications

Red meat consumption lags behind white meat consumption in South Africa and is losing ground steadily. Marketing efforts to stimulate the consumption of red meat among consumers should build upon aspect where consumers are already positive about beef such as: versatility, know how to prepare, good for entertaining, taste and nutrition (a nutritious meat and a good quality protein source). Furthermore the negative perceptions (affordability, fat and cholesterol content, long cooking time and could be a cause of health problems) should be improved.

Given the dynamic nature of the South African consumer environment with constant socio-economic changes and the influence of global consumer trends, the preferences and behaviour of South African consumers have a very dynamic nature. Subsequently it could be particularly valuable for the South African red meat industry to engage in follow-up surveys of this nature every few years in order to keep track of these dynamic changes.

Please contact the Primary Researcher on the project if you need a copy of the comprehensive report – Hester Vermeulen on hester@bfap.co.za

Amino acid composition of South African beef

Determining the amino acid profile of selected cuts from four age groups of South African beef, as additional to the previously approved project on the nutrient content of South African beef, in order to determine protein quality.

Industry Sector: Cattle and Small Stock

Research focus area: Red Meat Safety, Nutritional Value, Consumerism and Consumer Behaviour

Research Institute: Animal and Wildlife Science, University of Pretoria

Researcher: Prof Hettie Schönfeldt PhD

Team members

Title Initials Surname Qualification
Dr N. Hall Ph.D
Dr B. Pretorius Ph.D

Year of completion : 2017

Aims Of The Project

  • To determine the amino acid profile of South African beef
  • To determine the validity of using nitrogen and a specific Jones factor to define protein quantity
  • To determine the protein quality of South African beef in the context of human nutrition

Executive Summary

Globally protein quality is under the spotlight. The importance of protein quality was emphasized by both the 2007 and the 2011 Food and Agriculture Organization/ World Health Organization (FAO/WHO) Protein and amino acid requirements in human nutrition reports. These reports questioned the validity of current measures to determine crude protein content and protein absorption, and called for more research. Locally, the national Department of Health Directorate Food Control’s most recent legislation on food labelling and advertising requires that in order to make protein content claims, amino acid data in addition to crude protein (nitrogen), is needed.

During this project, raw and cooked beef cuts (prime rib, rump and shoulder) from all four age groups according to the South African classification system were sent for amino acid analyses at the ARC Irene Analytical laboratory.

Aligning with international debates, a literature review was completed to investigate existing literature on the validity of using the Jones factor of 6.25 to quantify the amount of protein from nitrogen within the red meat matrix. Amino acid data obtained was also compared to the use of the Jones factor to quantify the total protein content of red meat, and alternative factors were explored – similar to what has been done by Sosulki et al. in 1990. Mariotti et al (2008) also queried the use of 6.25 as the converting factor for red meat. Our study found that complete amino acid profiles of local beef amounted to 91% on average of protein based on total Nitrogen content (in weight). This indicates that there is an overestimation of protein in beef when the conversion factor of 6.25is used.

For local legislative purposes, the study found that all cuts from all age groups contain adequate quantities of the essential amino acids as required by the R.429 Food Labelling Legislation. This provides the scientific evidence required for South African beef to make protein content and functional protein claims on packaging and in marketing activities.

Technology transfers

  1. Participation of the Human Nutrition and Health Committee Meeting of the International Meat Secretariat (Canada, 1-3 July, 2015) (Addendum 2)
  2. Participation of the Human Nutrition and Health Committee Meeting of the International Meat Secretariat (Oslo, Norway, 15-18 July, 2016) (Addendum 2)

Reports to Industry

  1. NRF-THRIP progress report 2014
  2. NRF-THRIP final report 2015
  3. RMRD SA Progress report 2014
  4. RMRD SA Progress report 2015

Scientific articles

  1. Schönfeldt H.C., Pretorius B. and Hall, N. (2016) ‘Bioavailability of Nutrients’, In: Caballero, B., Finglas, P., and Toldrá, F. (eds.) The Encyclopedia of Food and Health vol. 1, pp. 401-406. Oxford: Academic Press.
  2. Article to be submitted after presenting “Updating and expanding the Food Composition Table for Western Africa“ at International Food Data Conferences (IFDC) – Official INFOODS conference. Center for Science in the Science and Technology Pole, Buenos Aires, Argentina. 11-13 October 2017.
  3. Article to be submitted after presenting “Amino acid and protein content of lean beef“ at International Food Data Conferences (IFDC) – Official INFOODS conference. Center for Science in the Science and Technology Pole, Buenos Aires, Argentina. 11-13 October 2017.

Theses

  1. Hall, N. 2015. Sustainable red meat from a nutrition perspective. University of Pretoria.

Conferences, symposia

  1. Co-author FAO/INFOODS (2017) Updating and expanding the Food Composition Table for Western Africa. 12th International Food Data Conference (IFDC) – Official INFOODS conference.
    Center for Science in the Science and Technology Pole, Buenos Aires, Argentina. 11-13 October 2017.
  2. Schönfeldt, H.C., Hall, N., Pretorius, B. and Van Deventer, M.M. (2017) Amino acid and protein content of lean beef. 12th International Food Data Conference (IFDC) – Official INFOODS conference. Center for Science in the Science and Technology Pole, Buenos Aires, Argentina. 11-13 October 2017.

Literature review

  1. Hall, N.G. and Schönfeldt, H.C. (2013) ‘Total nitrogen vs amino-acid profile as indicator of protein content of beef’, Food Chemistry. 140 (3): 608-612.

Popular Article

Globally protein quality is under the spotlight

Hettie Schönfeldt, Beulah Pretorius, Nicolette Hall, Maricia van Deventer

Department of Animal and Wildlife Sciences, Institute of Food, Nutrition and Well-being, University of Pretoria.

There has been much discussion regarding protein and amino acid requirements for both adults and children over the past few years.

Conventionally, protein content is determined by analysing the total nitrogen content in a food, and multiplying this by a standard conversion factor to obtain protein quantity – referred to as “crude protein”. Because proteins are made up of chains of amino acids, they can be hydrolysed and the separate amino acids can then be measured. The sum of the amino acids then represents the protein content (by weight) of the food. This is sometimes referred to as a “true protein”. This method however needs sophisticated equipment and is more expensive.

A project at the University of Pretoria aimed to determine the protein content and amino acid profile of South African beef (raw and cooked) and to establish if different cuts in the carcass and/or age of the animal influences the amino acid profile of South African beef.

Crude protein and amino acid analyses were done on 36 meat samples from Bonsmara carcasses from fat code two and all four age groups according to the South African Carcass Classification System. Three cuts (rump, prime rib and shoulder) were selected from each carcass and analyses were done on both raw and cooked meat.

Age had no significant effect on the sum of all amino acids (true protein) in both raw and cooked cuts. In the cooked cuts crude protein were found to be significantly different between the age groups for the different cuts. It should however be noted that these differences, although statistically significant, probably have little relevance in terms of human dietary requirements for protein as they differ by less than 2 g per 100 g cooked meat.

The data generated by this study is of further interest as discussions regarding the validity of nitrogen analyses for protein quantity determination and methods used to assess protein quality unfold. Table 1 shows the percentage of total amino acids to protein calculated with the Jones factor. It would be more appropriate to base estimates of protein on amino acid data.

Table 1: Percentage of sum of amino acids (‘true protein’) to protein calculated from total nitrogen using the Jones-factor (‘crude protein’)

Cut Raw / Cooked Percentage (Sum of amino acids / protein calculated from total nitrogen x 100)
Rump Raw 95%
Cooked 89%
Prime rib Raw 97%
Cooked 90%
Shoulder Raw 94%
Cooked 89%

Instead of simply focussing on total protein, attention has shifted to the greater importance of protein quality than actual quantity, emphasising the presence of individual amino acids in a food. One method of measuring protein quality is determining the quantity of the total essential amino acids and the digestibility of the protein source (PDCAAS). Data on the amino acid composition of foods is therefore essential in order to contribute to the current global discussion.

Protein quality answers two important questions namely, how much protein as well as what kind of protein should be consumed. Dietary proteins are classified as either being complete or incomplete. Some foods, such as animal source food, contain all indispensable (essential) amino acids and are referred to as a complete protein. Plant foods, on the other hand, lack one or more essential amino acid, which renders these sources of protein “incomplete”. Amino acids containing sulfur (including methionine and cysteine) and lysine most commonly limit the nutritional value (quality) of proteins in the human diet. Concentrations of these amino acids are, generally, considered lower in plant foods than in food of animal origin. In table 2 the lysine, methionine and cysteine content of commonly consumed food products is reported. Other essential amino acids, lysine and tryptophan, are also consistently found at lower concentrations in plant-based rather than animal-based foods. For example, tryptophan and lysine are limiting in corn; lysine in wheat, sorghum, and other cereals; and methionine in soybeans and other legumes. Including a small amount of lean beef in combination with plant-based foods can increase the protein quality of the meal.

Table 2: Lysine, methionine and cysteine content of commonly consumed food products

Food source  Food Range (mg/100g) from different studies
Lysine Methionine Cysteine
Animal products Beef and Veal (edible flesh) 531–591 147–182 78–182
Chicken (edible flesh) 384–606 88–215 64–114
Offal 375–506 138–181 62–132
Mutton and lamb (edible flesh) 438–589 131–198 63–144
Hen eggs 375–467 181–249 113–189
Fish (fresh, all types) 380–689 120–290 28–144
Legumes Chick-pea 406–463 34–106 50–94
Cowpea 394–479 50–119 48–106
Soya bean 313–477 53–114 51–114
Cereals & grain products Barley 159–250 63–250 81–194
Maize 100–214 53–175 38–200
Millet 100–244 84–246 69–169
Rice (brown or husked) 198–263 117–194 30–79
Rye (whole meal) 151–281 59–181 85–156
Wheat (whole grain) 131–249 63–156 111–212
Roots and tubers Potato 163–488 54–125 7–81

The protein and indispensable amino acid profile of lean beef is reported in table 3. This is compared to the recommended protein requirement of 0.66 g/kg body weight/ day and the amino acid scoring pattern for children older than 3 years, adolescents and adults. According to the South African Food Based Dietary Guideline a serving of red meat can be eaten daily, but should not be more than 90g/day.

Table 3: Dietary protein and indispensable amino acid profile of cooked beef, cow’s milk, cooked soya beans compared to the recommended amino acid scoring pattern for children (3-10years), adolescents and adults

Cooked lean beef Full cream cow’s milk Cooked soya beans Recommended protein and amino acid scoring pattern for older children, adolescents and adults
“Crude” protein (g/100g) 31.8 3.25 18.21 0.66 g/kg/day50kg person = 33g

70 kg person = 46g

Amino acid
(mg/g total protein)
Histidine (His) 28 28 25 16
Isoleucine (Ile) 44 54 44 30
Leucine (Leu) 74 94 74 61
Lysine (Lys) 97 79 61 48
Sulphur amino acids (SAA) Methionine (Met) + Cysteine (Cys) 63 39 27 23
Aromatic amino acids (AAA) Phenylalanine (Phe) + Tyrosine (Tyr) 73 97 83 41
Threonine (Thr) 44 48 40 25
Tryptophan (Thp) 16 12 13 6.6
Valine (Val) 46 59 46 40

The study found that South African beef from all age groups adheres to the requirements as set out by the Department of Health to be labelled and proclaimed as a complete, quality protein.

It is of interest to note that the true protein was consistently lower in the cooked meat compared to the raw meat and that the different cuts varied in the respective amino acid profiles. While the measurement of crude protein (total nitrogen multiplied by a factor) is adequate for many purposes, amino acid data would provide a better assessment of the nutritional value of a food. Through this study the amino acid profile of South African lean beef was determined and is available for future studies.

Acknowledgement: This study was funded by Red Meat Research and Development of South Africa (RMRD SA) and the National Research Foundation Technology and Human Resources for Industry Programme (NRF-THRIP) (Project id: Tp1208076284).

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Prof H.C. Schonfeldt on hettie.schonfeldt@up.ac.za