White fish authentication by COIBar-RFLP: Toward a common strategy for the rapid identification of species in convenience seafood

• We investigated labeling accuracy on 20 seafood products from Southern Italy markets.
• A total of 54 samples were processed for product authentication.
• We identified products to the species level via DNA barcoding.
• Mislabeling was observed in 35% of the convenience seafood products.
• HinfI is suitable for fish authentication by COIBar-RFLP in seafood products.

The global trade and the increased demand for seafood products have encouraged the common practice of replacement of valuable species with species of lower value worldwide. The species of the genus Merluccius are often subject to fraudulent substitution due to their high commercial interest. The present investigation of labeling accuracy on 54 samples taken from 20 convenience seafood products collected from Southern Italy markets, allowed the identification of four species through DNA barcoding: Gadus chalcogrammus, Merluccius merluccius, Merluccius productus and Merluccius paradoxus. Mislabeling was observed in seven of 20 (35%) products (frozen breaded steaks and fish fingers), six of which (30%) were labeled as hake (M. merluccius). To reduce analysis time of fish species authentication, a COIBar-RFLP, using DNA barcoding in combination with PCR-RFLP methods, was performed for species discrimination. The restriction enzyme HinfI yielded differential digestion patterns suitable for unveiling inconsistencies between product labels and genetic species identification. The COIBar-RFLP represents an effective tool for fish authentication in convenience seafood and responds to the emerging interest in molecular identification technologies that reduce processing time and eliminate the need for lab-based DNA sequencing.