An indirect ELISA and a PCR technique for the detection of Grouper (Epinephelus marginatus) mislabeling

An indirect enzyme-linked immunosorbent assay (ELISA) and a multiplex polymerase chain reaction (PCR) procedure was applied for the detection of Grouper (Epinephelus marginatus) mislabelling in the fish market. An indirect ELISA (microtiter-plate format) using two monoclonal antibodies (3D12 and 1A4) was assayed and multiplex PCR performed using species-specific primers of the 5S rDNA gene for the rapid authentication of grouper. A total of 70 commercial fish fillet samples, collected from local markets and supermarkets, labelled as grouper were analysed: 12 of the 70 samples were confirmed to be Grouper. The PCR technique permitted the detection of Nile Perch (Lates niloticus) in the commercial fillet samples, which was not possible using ELISA. The results suggest that both ELISA and PCR are specific and reliable tools for the detection of Grouper mislabelling/adulteration and the accurate implementation of traceability for successful regulatory food controls.