Where is the game? Wild meat products authentication in South Africa: a case study

Abstract

BackgroundWild animals’ meat is extensively consumed in South Africa, being obtained either from ranching, farming or hunting. To test the authenticity of the commercial labels of meat products in the local market, we obtained DNA sequence information from 146 samples (14 beef and 132 game labels) for barcoding cytochrome c oxidase subunit I and partial cytochrome b and mitochondrial fragments. The reliability of species assignments were evaluated using BLAST searches in GenBank, maximum likelihood phylogenetic analysis and the character-based method implemented in BLOG. The Kimura-2-parameter intra- and interspecific variation was evaluated for all matched species.ResultsThe combined application of similarity, phylogenetic and character-based methods proved successful in species identification. Game meat samples showed 76.5% substitution, no beef samples were substituted. The substitutions showed a variety of domestic species (cattle, horse, pig, lamb), common game species in the market (kudu, gemsbok, ostrich, impala, springbok), uncommon species in the market (giraffe, waterbuck, bushbuck, duiker, mountain zebra) and extra-continental species (kangaroo). The mountain zebra Equus zebra is an International Union for Conservation of Nature (IUCN) red listed species. We also detected Damaliscus pygargus, which is composed of two subspecies with one listed by IUCN as ‘near threatened’; however, these mitochondrial fragments were insufficient to distinguish between the subspecies. The genetic distance between African ungulate species often overlaps with within-species distance in cases of recent speciation events, and strong phylogeographic structure determines within-species distances that are similar to the commonly accepted distances between species.ConclusionsThe reliability of commercial labeling of game meat in South Africa is very poor. The extensive substitution of wild game has important implications for conservation and commerce, and for the consumers making decisions on the basis of health, religious beliefs or personal choices.Distance would be a poor indicator for identification of African ungulates species. The efficiency of the character-based method is reliant upon availability of large reference data. The current higher availability of cytochrome b data would make this the marker of choice for African ungulates. The encountered problems of incomplete or erroneous information in databases are discussed.

Advances in Authenticity Testing for Meat Speciation

“…In both studies, BOLD was used to identify sequences at the species level. In South Africa a DNA barcoding approach was effectively used to confirm that the reliability of commercial labeling of game meat is very poor (D'Amato et al, 2013) and for species identification in forensic wildlife cases (Dalton and Kotze, 2011). In spite of the advantages of DNA barcoding, currently it is not able to identify multiple species in meat mixtures, requiring the use of other methods, such as real-time PCR or next-generation sequencing (Hellberg and Morrissey, 2011;Kane and Hellberg, 2016).…”

Meat trade: Need for international standardization?

“…The finding of approximately 70% substitution for red meat products of domestic or wild animals [1,2] gained sensational publicity, similarly to the finding of beef substituted by horse meat in Europe.…”

“…Our results based on cytb and COI DNA sequence information showed a large proportion of cow (42.6%), and a variety of undeclared wild species (41.6%) with one CITES Appendix I listed species, followed by kangaroo (7%) and a minor proportion of horse, sheep and pork [2]. A similar approach also allowed for the detection of rat, fox, ferret, and duck meat sold as lamb in China (Shenzhen Academy of Metrology and Quality Inspection, unpublished data).…”

On the potential of using peculiarities of the protein intrinsic disorder distribution in mitochondrial cytochromebto identify the source of animal meats

“…5 According to the market studies conducted in Mexico, Turkey, and South Africa, 20-70% of a variety of meat products are mislabeled and contain meat species that are not included to the package labels. [6][7][8][9] Meat adulteration is common in USA too. Based on the 1995 analysis of ground meat products in Florida, USA, mislabeling was found in 16.6% of the products tested.…”