DNA barcode authentication reveals highly fraudulent cod commerce in Porto Alegre, Brazil

Abstract Through the DNA barcoding technique using the cytochrome oxidase subunit I (coI) mitochondrial gene, a high degree of fraudulent commerce of Cod (Bacalhau in Portuguese) was detected in the city of Porto Alegre, Brazil. Tested products included frozen and dried salted fish during the Easter period, the season with the highest Cod consumption. The sale of Cod products in Brazil is controlled by governmental technical regulations restricting the Cod designation to salted and dried salted products made from three species of Gadus. The results of this investigation revealed a high level of fraud of various types against consumers. Of 10 tested products, seven were identified as fraudulent, including distinct species from the ones indicated in the labels, constituting cases of substitution for cheaper fish species, or species not allowed to be sold as Cod, or prepared in discordance with standard requirements of preparation (salted or dried salted), and were therefore considered mislabeled under Brazilian technical regulations.