DS CEN/TS 17303:2019

Foodstuffs - DNA barcoding of fish and fish products using defined mitochondrial cytochrome b and cytochrome c oxidase I gene segments

Scope

This method specifies a procedure for the identification of raw, cold smoked, salted, frozen or cooked (boiled, fried, deep-fried, hot smoked) single fish and fish filets to the level of genus or species.
The identification of fish species is carried out by PCR amplification of either a segment of the mitochondrial cytochrome b gene (cytb) or the cytochrome c oxidase I gene (cox1, syn COI) or both, followed by sequencing of the PCR products and subsequent sequence comparison with entries in databases. The methodology allows the identification of a large number of commercially important fish species.
The decision whether the cytb or cox1 gene segment or both are used for fish identification depends on the declared fish species, the applicability of the PCR method for the fish species and the availability of comparative sequences in the public databases.
This standard is usually unsuitable for the analysis of highly processed foods, e. g. tins of fish, with highly degraded DNA where the fragment lengths are not sufficient for amplification of the targets. Furthermore, it is not applicable for complex fish products containing mixtures of two or more fish species.