Fish species identification using PCR-RFLP analysis and lab-on-a-chip capillary electrophoresis: application to detect white fish species in food products and an interlaboratory study.

Identification of 10 white fish species associated with U.K. food products was achieved using PCR-RFLP of the mitochondrial cytochrome b gene. Use of lab-on-a-chip capillary electrophoresis for end-point analysis enabled accurate sizing of DNA fragments and identification of fish species at a level of 5% (w/w) in a fish admixture. One restriction enzyme, DdeI, allowed discrimination of eight species. When combined with NlaIII and HaeIII, specific profiles for all 10 species were generated. The method was applied to a range of products and subjected to an interlaboratory study carried out by five U.K. food control laboratories. One hundred percent correct identification of single species samples and six of nine admixture samples was achieved by all laboratories. The results indicated that fish species identification could be carried out using a database of PCR-RFLP profiles without the need for reference materials.