Sparid species discrimination by COIBar-RFLP in commercial products

Abstract

Processed seafood products are subject to fraudulent species substitution practices that pose problems not only economically but also for human health due to the risk of allergies. DNA-based molecular techniques offer an undoubted contribution to unraveling commercial fraud in processed seafood products, and several investigations have been conducted to develop specific and rapid assays for the identification of fish species. In this context, we hypothesize that the Cytochrome Oxidase I (COI) Barcode-Restriction Fragment Length Polymorphisms (COIBar- RFLP) strategy may be a useful molecular tool to quickly assess the authenticity of seafood products because (i) it takes advantage of the specific discriminatory power of the COI gene as a barcode and of the robust Restriction Fragment Length Polymorphism methodology and (ii) the interspecific variation in the digestion pattern obtained using the restriction enzymes allows bypassing the gene sequencing step. The Sparidae family includes species of high commercial value and many sparid species are difficult to recognize considering only their morphological features; thus, misidentifications are frequent. The aim of this work was to identify sparid species in processed products using the COIBar-RFLP strategy with the MspI restriction enzyme which yielded differential digestion patterns and unveiled two cases of species substitution. The proposed methodology could be used in food control laboratories to combat the widespread habit of fraudulent species substitution in the fishing industry.