PCR-based methodology for the authentication of grouper (Epinephelus marginatus) in commercial fish fillets

In an attempt to authenticate commercial frauds in fish fillets of grouper (Epinephelus marginatus) by being substituted with those of Nile perch (Lates niloticus) and wreck fish (Polyprion americanus), a polymerase chain reaction (PCR) method, based on the design of specific primers of these species was explored here. The oligonucleotides, which were designed from the 12S ribosomal RNA gene, generated PCR fragments of 100, 138 and 169 bp length for grouper, wreck fish and Nile perch respectively. The specificity of the primers was tested against more than 50 different fish species. Moreover, in this work 70 commercial fish fillets samples were analysed by this methodology; 58 out of them confirmed to be incorrectly labelled. The results suggest that this method may be a reliable tool for the detection of grouper adulteration. Also, this technique may help implementation of traceability systems in the seafood industry.