Species authentication of canned mackerel: Challenges in molecular identification and potential drivers of mislabelling

The market for canned mackerel is growing, due to their competitive price and to the excellent properties of the meat. However, the weak rules of current legislation, coupled with the loss of discrimination power due to being obliged to use short barcode regions, open up new challenges for traceability in processed products. In this study, for the first time, we applied a two-step mini-barcoding approach to identify canned mackerel sold in Italian markets and make assumptions on the potential drivers of mislabelling. Preliminary identification was performed using mini-barcode universal primers targeting a COI-fragment; then, in order to discriminate within the complex Scomber colias/S. japonicus/S. australasicus, we applied a second step, using new specific primers designed in the mitochondrial control region (D-loop). Comparison between labels and molecular identifications highlighted that the chance of mislabelling could be either 45% or 0%, depending on the interpretation of the generic terms used on the labels. Therefore, the study revealed that the ambiguous use, in the ingredient list, of ‘umbrella’ terms for naming fish species, such as ‘sgombro’ could be related to geographic origin of products and creates opportunities for fraudulent activities, but also misleads consumers. In light of this pattern, an urgent update of European legislation is needed to face current and future challenges for full chain traceability.