Meat species substitution: when what you see is not what you get

Karen Horsburgh (BSc.Diet) FACTS (Food and Allergen Consulting and Testing Services)

Food fraud is big business. Although the true extent is uncertain, such practices are calculated to cost the global food industry up to £25 billion (over ZAR 300 billion) per year and the UK Food Standards Agency (FSA) estimates that up to 10% of commercial food products may be counterfeit.1-2 In this time of rapid globalisation, when a single processed food product may contain ingredients sourced from a dozen different nations, numerous opportunities exist for unscrupulous food producers to fraudulently substitute or add ingredients which are cheaper, but not necessarily desirable.

What is the risk of meat species substitution, why and how does it occur, and what can be done to ensure the authenticity of the meat products that is supplied? This article seeks to shed some light on these topics.

It is no secret that the recent meat adulteration scandal has shaken the food industry over the last few weeks, presenting a plethora of new challenges to food manufacturers and compromising consumer confidence in the functioning of the meat supply chain, both locally and globally. This shocking issue, which came to light in January 2013, involved foods labelled as beef in the EU, which was found to contain undeclared horse meat, as well as other unlisted meats such as pork. Consequently, a number of big food industry names have been caught off guard. These include the UK supermarket chains Tesco, Iceland and Lidl, the German discounter Aldi, the frozen-foods processor Findus and the global fast food giant Burger King, all of which have all been implicated in marketing fraudulent meat.

Such meat adulteration scandals are not limited to horsemeat, and they are certainly not limited to the EU.

A recent meat authentication study conducted by Food & Allergy Consulting & Testing Services (FACTS) food scientist, Dr. Donna Cawthorn, hit headline news in December 2012, when it was revealed that 68% of 139 processed meat products obtained from the South African market contained species not declared on the label, including undeclared pork, donkey, goat and water buffalo. In a related story, the problem of species substitutions involving game meat served at local restaurants was simultaneously exposed.

Dr Donna Cawthorn also published a set of results from her PhD study conducted at the University of Stellenbosch in 2011, in which DNA testing was used to reveal that 9% of fish samples collected from seafood wholesalers in South Africa and a startling 31% of those collected from retail outlets were mislabelled with regards to species.3

Whether deliberate or unintentional, the effects of meat (or fish) product misdescription are similar, and include consumer deception, potential health risks and the inability of individuals to choose products for the sake of religious and ethical beliefs.

 

Why and how is fraud perpetuated?

Due to their high prices, food products such as meat and fish are highly prone to substitution or adulteration, and such practices are often relatively simple to get away with. The flesh of many meat species differs only subtly in appearance and texture, making it difficult to identify the species based on visual inspection. Once meat is comminuted and incorporated into value-added products, however, identification based on appearance and other sensory parameters becomes virtually impossible. At another level, substitution of meat ingredients may involve the use of cheaper ingredients from the same declared species, but from different body parts (typically offal, connective tissue or blood), or the substitutes may be non-meat ingredients (e.g. plant or dairy sources).4 A further significant concern is the potential for meat products to be contaminated with undeclared species during processing. Cross-contamination can arise when poorly cleaned equipment or utensils are used for processing meat from two or more different meat species.

Apart from the concerns that meat substitution or adulteration generate from economical, religious or ethical viewpoints, counterfeit components may be toxic (e.g. melamine) and the undeclared addition of some ingredients (e.g. soy, wheat, dairy) can pose health risks for consumers with food allergies /intolerances.

 

Ensuring meat authenticity

While knowing your meat suppliers and auditing them regularly may be an obvious step in protecting the authenticity of meat products, in many cases food fraud cannot be discovered by following a paper trail and detection requires ‘state of the art’ scientific analysis. Today, DNA-based techniques are considered the most appropriate methods for making species identifications as DNA is present and is identical in all tissue types, is relatively stable even at high temperatures and because the diversity afforded by the genetic code allows the differentiation of very closely-related species.

The detection of the complete substitution of a single meat species with another is one of the more simple scenarios for identifying food fraud. In general, DNA sequencing conducted on a queried sample will produce a DNA sequence or ‘fingerprint’ which can compared to a set of known reference sequences in a credible genetic database. The identity of the specimen can thereby be established, which is either the same or different to the one expected. Investigating the partial substitution or adulteration of meat is considerably more difficult, since it is normally necessary to know the possible identity of the adulterant before it can be detected. To help alleviate the aforementioned difficulties, an animal species screening method which allows the detection of up to 24 different animal species in a single reaction is useful. This method, which relies on the use of species-specific DNA probes to detect certain target DNA sequences, significantly reduces the costs and labour required to ensure product authenticity.

For more information visit http://www.factssa.com/newsletters.html.

Food fraud is indeed a food industry issue. Consumers are highly reliant on the accurate and complete declaration of food constituents to enable them to make product choices that are consistent with their lifestyles. Brand loyalty can be severely compromised should this be found not to be the case.

Meat adulteration is not new…

  • The adulteration of foods with undeclared ingredients or the substitution of high-valued foods with lower-valued varieties for illicit financial gain is probably as old as commerce itself.
  • In 1981, the Australian meat industry came into the spotlight when it was found that meat from horse, donkey, buffalo and kangaroo were substituted for higher-priced Australian beef exported to the USA. This ‘meat substitution scandal’ threatened Australia’s lucrative beef export industry.14
  • Floes-Munguia et al. (2000) detected undeclared horse meat in 9 of 23 (39%) uncooked commercial hamburger meat samples collected from Mexican markets, while undeclared horse and pork meat were detected in 5 of 17 (29%) Mexican sausage (chorizo) samples.15
  • In 2003, it was revealed on BBC that vast quantities of frozen chicken entering the UK each week were injected with undeclared beef proteins. Simultaneous testing by the FSA showed that pork protein was present in at least half of the chicken meat destined for the UK catering industry, which was in fact marked as ‘Halaal’.16
  • DNA testing conducted by Farouk et al. (2006) on 30 food samples collected from the Malaysian market, which were not expected to contain pork, revealed that three were contaminated with pork material, two of which were declared as ‘Halaal’ products.17
  • In a study conducted in Turkey, Ayaz et al. (2006) used the ELISA to test 24 sausage, 13 salami and 11 frankfurter products, all declared only as beef. The authors found that 39%, 36% and 27%, respectively, contained poultry as well as beef. Of six raw meat samples declared as beef, one sample was found to be substituted with donkey, and another with deer meat.18

 

 

More information on this topic

 

1 Shears, P. (2010). Food fraud – a current issue but an old problem. British Food Journal, 112(2), 198-213.

2 Spink, J. & Moyer, D.C. (2011). Defining the public health threat of food fraud. Journal of Food Science, 76(9), 157-163.

3 Cawthorn, D.M., Steinman, H.A. & Witthuhn, R.C. (2011). DNA barcoding reveals a high incidence of fish species misrepresentation and substitution on the South African market. Food Research International, 46(1), 30-40.

4 Young, O.A. Frost, D.A., West, J. & Braggins, T.A. (2001). Analytical methods. In: Meat Science and Applications (edited by Y.H. Hui, W.K. Nip, R.W. Rogers & O.A. Young). Pp. 103-126. New York: Marcel Dekker.

5 Anonymous (2011). South African Muslims furious at ‘halal pork’ scandal. BBC News Africa, 16 November 2011. URL http://www.bbc.co.uk/news/world-africa-15753835.

6 Magubane, T. (2011). Meat racket exposed. The Witness, 12 November 2011. URL www.witness.co.za/index.php?show

 content&global%5B_id%5D=71736.

7 Schroeder, F. (2011). ‘Pork sold as halaal meat’. Cape Argus, 10 November 2011. URL www.iol.co.za/capeargus/pork-sold-as-halaal-meat-1.1175676.

8 Schroeder, F. (2011). Managers ‘knew of pork sold as halaal’. Cape Argus, 18 November 2011. URL www.iol.co.za/cape

 argus/managers-knew-of-pork-sold-as-halaal-1.1181580.

9 Vadi, A. (2011). Muslim community angry at yet another Halaal meat scandal. CII Broadcasting, 10 November 2011. URL http://www.ciibroadcasting.com/2011/11/10/muslim-community-angry-at-yet-another-halaal-meat-scandal

10 Wiener, M. (2011). Questionable meat products in the spotlight. Eye Witness News, 10 November 2011. URL http://www.ewn.co.za/Story.aspx?Id=77224.

11 Lenstra, J.A. (2003). DNA methods for identifying plant and animal species in food. In: Food Authenticity and Traceability (edited by M. Lees). Pp. 34-53. Florida, USA: CRC Press.

12 Mackie, I.M. (1996). Authenticity of fish. In: Food Authentication (edited by P.R. Ashurt & M.J. Dennis). Pp. 140-170. London, UK: Blackie Academic and Professional.

13 Woolfe, M. & Primrose, S. (2004). Food forensics: using DNA technology to combat misdescription and fraud. Trends in Biotechnology, 22, 222-226.

14 Grabosky, P. (1989). The meat substitution scandal of 1981. In: Stains on a white collar: fourteen studies in corporate crime or corporate harm (edited by P. Grabosky & A. Sutton). Pp. 60-75. Sydney : Federation Press.

15 Floes-Munguia, M.E., Bermudez-Almada, M.C. & Vazquez-Moreno, L. (2000). Detection of adulteration in processed traditional meat products. Journal of Muscle Foods, 11, 319-332.

16 Anonymous (2003). Call to ban rogue meat in chicken. BBC News, 20 June 2003. URL http://news.bbc.co.uk/2/hi/uk_news/3006192.stm

17 Farouk, A-E., Batcha, M.F., Greiner, R., Salleh, H.M., Salleh, M.R. & Sirajudin, A.R. (2006). The use of a molecular technique for the detection of porcine ingredients in the Malaysian food market. Saudi Medical Journal, 27(9), 1397-1400.

18 Ayaz, Y., Ayaz, N.D. & Erol, I. (2006). Detection of species in meat and meat products using enzyme-linked immunosorbent assay. Journal of Muscle Foods, 17, 214–220.