A Fast and Simple DNA Mini-barcoding and RPA Assay Coupled with Lateral Flow Assay for Fresh and Canned Mackerel Authentication

Nowadays, food authentication is more and more required given its relevance in terms of quality and safety. The seafood market is heavily affected by mislabelling and fraudulent substitutions/adulterations, especially for processed food products such as canned food items, due to the loss of morphological features. This study aims to develop new assays based on DNA to identify fresh mackerel (Scomber spp.) and commercial products. A new primer pair was de novo designed on the 5S rRNA gene and non-transcribed spacer (NTS), identifying a DNA mini-barcoding region suitable for species identification of processed commercial products. Moreover, to offer a fast and low-cost analysis, a new assay based on recombinase polymerase amplification (RPA) was developed for the identification of fresh ‘Sgombro’ (Scomber scombrus) and ‘Lanzardo o Occhione’ (Scomber japonicus and Scomber colias), coupled with the lateral flow visualisation for the most expensive species (Scomber scombrus) identification. This innovative portable assay has great potential for supply chain traceability in the seafood market.