Fish Forensics using a combination of SSCP analysis and sequencing of a 16S mtDNA gene fragment: Preliminary results indicate inconsistent product labelling

The seafood industry is one of the most important and complex industries worldwide. Product identification is critical to the industry and is complicated because, even in Australia, literally thousands of marketing names are used. In addition, an increasing trend to sell fish species as skinless and boneless fillets makes identification post-processing highly problematic. Not surprisingly, there is increasing concern amongst consumers and regulatory authorities regarding the veracity of labelling of such products. The seafood industry is aware of the need for consistent and accurate labelling as incorrect identification of fish fillets, whether deliberate or accidental, can have serious negative effects on consumer confidence. Here, we demonstrated that single-strand conformation polymorphism analysis, coupled with direct sequencing, of the 16S mtDNA gene region, can provide a rapid, efficient and reliable method of identifying fish fillets sold in south-eastern Australia. Fillets of barramundi, cod, hake, hoki and snapper were purchased and compared first using single strand conformation polymorphism analysis with comparisons against taxonomically verified Australian reference samples. All fillet and reference samples were then sequenced to determine the efficiency of the single strand conformation
polymorphism technique and make comparisons with sequences available from
GenBank for imported products. Our results revealed labelling inconsistencies due to multiple marketing names being applied to single species and multiple species being marketed under a single name. In addition to this, we found difficulties in identifying products using fragment-based methods especially in regard to imported products.