Identification of Mislabelling in Frozen Fish Fillets Based on DNA Barcoding Analysis

A number of studies have shown that mislabelling and species substitutions in fish products are very common worldwide. This fraud has two major aspects: economics and health. Moreover, poor trading, and neglecting the species conservation status are growing threats for fish stocks. First the type and extend of this fraud in fish must be detected in order to take proper actions. As some markers (e.g. protein analysis and morphological features) can fail, DNA markers, especially sequencing of cytochrome oxidase I gene (or DNA barcoding), is becoming a more widely preferred methodology for species identification. In this study, DNA barcoding technique was employed to confirm the species names written on the product packages of fish fillets purchased from the market. The fillets were labeled as Nile tilapia (Oreochromis niloticus). Among the 15 fillet samples analyzed, only 4 of them were labeled correctly. Seven (47%) of them were found to originate from pangasius (Pangasianodon hypophthalmus) and three of them were found to originate from a different tilapia species (Oreochromis mossambicus). This paper revealed a significant mislabelling of frozen fish fillets in Turkey. Customers are making informed decisions based on many reasons (like health issues or palate) and they have the right to eat what they think they are paying for. The results indicate the necessity for taking immediate actions and regulations against fraud in food items to sustain food quality and safety.


Asensio, L., González, I., García, T. & Martín, R. (2008). Determination of food authenticity by enzyme-linked immunosorbent assay (ELISA). Food Control, 19: 1-8.

Barbuto, M., Galimberti, A., Ferri, E., Labra, M., Malandra, R., Galli, P. & Casiraghi, M. (2010). DNA barcoding reveals fraudulent substitutions in shark seafood products: the Italian case of Palombo (Mustelus spp.). Food Research International, 43: 376-381.

Bénard-Capelle, J., Guillonneau, V., Nouvian, C., Fournier, N., Le Loët, K. & Dettaï, A. (2015). Fish mislabelling in France: Substitution rates and retail types. Peer J, 2(9): e714.

Cawthorn, D-M., Steinman, H. A. & Witthuhn, R. C. (2012). DNA barcoding reveals a high incidence of fish species misrepresentation and substitution on the South African market. Food Research International, 46(1): 30–40.

Changizi, R., Farahmand, H., Soltani, M., Asarch, R. & Ghiasvand, Z., (2013). Species identification reveals mislabelling of important fish products in Iran by DNA barcoding. Iranian Journal of Fisheries Sciences, 12: 783–791.

Di Pinto, A., Di Pinto, P., Terio, V., Bozzo, G., Bonerba, E., Ceci, E. & Tantillo, G. (2013). DNA barcoding for detecting market substitution in salted cod fillets and battered cod chunks. Food Chemistry, 141: 1757–1762.

Di Pinto, A., Mottola, A., Marchetti, P., Bottaro, M., Terio, V.; Bozzo, G., Bonerba, E., Ceci, E. & Tantillo, G. (2015). Packaged frozen fishery products: Species identification, mislabelling occurrence and legislative implications. Food Chemistry, 194: 279–283.

FAO (2010). The State of World Fisheries and Aquaculture. ( (Access date: 10.06.2019)

FAO (2017). Fishery and Aquaculture Statistics. Global production by production source 1950-2015 (Fishstat J). In: FAO Fisheries and Aquaculture Department [online]. Rome. ( (Access date: 15.06.2019).

FAO (2018a). Overview of food fraud in the fisheries sector, by Alan Reilly. Fisheries and Aquaculture Circular No. 1165. Rome, Italy.

FAO (2018b). The State of World Fisheries and Aquaculture. ( (Access date: 10.06.2019)

Filonzi, L., Chiesa, S., Vaghi, V. & Marzano, F. N. (2010). Molecular barcoding reveals mislabelling of commercial fish products in Italy. Food Research International, 43: 1383-1388.

Galimberti, A., Mattia, F. D., Losa, A., Bruni, I., Federici, S., Casiraghi, M., Martellos, S. & Labra, M. (2013). DNA barcoding as a new tool for food traceability. Food Research International, 50(1): 55-63.

Hasegawa, M., Kishino, H. & Yano, T. (1985). Dating of the human-ape splitting by a molecular clock of mitochondrial DNA. Journal of Molecular Evolution, 22(2): 160–174

Hebert, P. D. N., Cywinska, A., Ball, S. L. & de Waard, J. R. (2003). Biological identifications through DNA barcodes. Proceedings of The Royal Society B: Biological Sciences, 270(1512): 313-321.

Hubalkova Z., Kralik P., Tremlova, B. & Rencova, E. (2007). Methods of gadoid fish species identification in food and their economic impact in the Czech Republic: A review. Veterinarni Medicina, 52: 273-292. Keskin, E. & Atar, H. H. (2011). İşlenmiş Kalamar Ürünlerinde Sitokrom Oksidaz I Gen Dizileri Kullanılarak Tür Tayini. Gıda, 36(6): 343-348.

Keskin, E. & Atar, H. H. (2012). Molecular identification of fish species from surimi-based products labelled as Alaskan pollock. Journal of Applied Ichthyology, 28: 811-814.

Kumar, S., Stecher, G. & Tamura, K. (2016) MEGA7: Molecular Evolutionary Genetics Analysis version 7.0 for bigger datasets. Molecular Biology and Evolution, 33(7): 1870-1874.

Maclean, J. (1984). Tilapia – The aquatic chicken. ICLARM, Makati, Manila. 7(1): 17.

Neto, D. A. P. (2013). Detec_cã de adultera_cão de espécies em pescado e derivados por meio detécnica de DNA Barcoding. Belo Horizonte (MG), Universidade Federal de MinasGerais, 43p. Available at http://

Özcan-Gökçek, E., Karahan, B. & Gamsız, K. (2012). Bir Nil Tilapya (Oreochromis niloticus L., 1758) populasyonunda BLUP yöntemiyle hasat ağırlığı için damızlık değer tahmini. Ege Journal of Fisheries and Aquatic Sciences, 29(1): 15-19.

Rehbein, H. (1990). Electrophoretic techniques for species identification of fishery products. Zeitschrift für Lebensmittel-Untersuchung und Forschung, 191(1): 1-10.

Smith, P. J., McVeagh, S. M. & Steinke, D. (2008). DNA barcoding for the identification of smoked fish products. Journal of Fish Biology, 72: 464–471.

Staffen, C. F., Staffen, M. D., Becker, M. L., Löfgren, S. E., Muniz, Y. C. N., de Freitas R. H. A. & Marrero A. R. (2017). DNA barcoding reveals the mislabelling of fish in a popular tourist destination in Brazil. Peer J, 5: 1–13.

Strauss, R. E. & Bond, C. E. (1990). Taxonomic methods: morphology, pp 109-140. In: Schreck, C. B. & Moyle, P. B. (Eds.). Methods for fish biology. American Fisheries Society, Maryland. 704p.

TurkStat (2018). Turkish Statistical Institute. (Access date: 10.06.2019) Ward, R. D., Zemlak, T. S., Innes, B. H., Last, P. R. & Hebert, P. D. (2005). DNA barcoding Australia’s fish species. Philosophical Transactions Royal Society B, 360: 1847-1857.

Ward, R. D., Hanner, R. & Hebert, P. D. N. (2009). The campaign to DNA barcode all fishes. Journal of Fish Biology, 74(2): 329– 356.

Willette, D. A., Simmonds, S. E., Cheng, S. H., Esteves, S., Kane, T. L., Nuetzel, H., Pilaud, N., Rachmawati, R. & Barber, P. H. (2017). Using DNA barcoding to track seafood mislabeling in Los Angeles restaurants. Conservation Biology, 31(5): 1076-1085.

World Bank (2013). FISH TO 2030. Prospects for Fisheries and Aquaculture. World Bank Report Number 83177-GLB. ( (Access date: 28.06.2019)

Kaynak Göster