Seafood has been identified as one of the foods vulnerable to mislabelling and fraud. In addition, Singapore has a high consumption of seafood (average 22kg/per capita/year). Researchers at the National University of Singapore conducted a survey to verify the labelling/description of seafood species. Eighty eight samples were collected from retail outlets and restaurants. Using mitochondrial DNA barcoding of the cytochrome c oxidase Subunit-I to identify seafood species, 42 different species were identified. In total, 26% (23) of the samples were mislabelled. The three most frequently mislabelled fish were Anoplopoma fimbria (Sablefish) sold as Black Cod, Dissostichus eleginoides (Patagonian toothfish) sold as Cod or Seabass, and Pangasianodon hypophthalmus (Iridescent shark) sold as Dory or Bocourti. Restaurants did not show any evidence of mislabelling, and all the mislabelled samples came from retail outlets.
Scallops are high value seafood products usually sold without their characteristic shells. Each species differs in its taste and value with the Pecten spp. scallops attracting higher prices in Europe. German researchers have developed a multiplex real-time PCR method to reliably identify the main commercial scallop species: Pecten spp. (usually King scallop P. maximus), Mizuhopecten yessoensis (Japanese scallop), and Placopecten magellanicus (Atlantic sea scallop). Primers and probes based on mitochondrial 16S rRNA gene amplifying fragments of 138–198 bp were used, and non-targeted species gave either no fluorescent signal or cycle numbers (Cq) very different from the targeted species. The newly developed assay was tested on commercial samples from German supermarkets and fishmongers accompanied by simultaneous verification through Sanger sequencing, which revealed a high mislabelling rate of 48%, especially for products purchased at fishmongers.
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This paper records the outcome of the latest and largest multi-species, transnational survey of fish labelling to date, which demonstrates an apparent reduction of seafood mislabelling in Europe. The authors argue that recent efforts in legislation, governance, and outreach have had a positive impact on industry regulation coupled with successful molecular biology methodology.
Read more at: http://usir.salford.ac.uk/37241/1/Mariani%20et%20al_Final-FEE-Dec2015.pdf
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