Are we sure we eat what we buy? Fish mislabelling in Buenos Aires province, the largest sea food market in Argentina

Abstract The detection of substituted or mislabeled seafood may have different consequences on consumers and the environment, including economic losses due to potential commercial fraud, public health effects, uncontrolled impacts on fish species of threatened status, and damage to populations due to overfishing. The molecular identification of processed meat or specimens that lack diagnostic body parts is a highly effective tool for species identification and law enforcement. DNA barcoding was used to assess levels of mislabeling or substitution through molecular identification of fresh fish fillets sold in different seafood markets throughout the Province of Buenos Aires, Argentina. The total substitution rate was 21.34% with most of the replacements involving Chondrichthyes (22 of the 35 mislabeled fillets), mainly the sharks Galeorhinus galeus (8 times) and Mustelus schmitii (9 times) being sold as something else. These results highlight the problems generated by mislabelling, to a great extent an economic problem (fraud), and also a conservation problem, due to the exploitation of threatened species. The present study reinforces a calling for enlarged traceability of food products and the assessment of authenticity of fillets by skilled supervisory authorities.