Species identification of Alaska pollock, Gadus spp., and Micromesistius spp. in cod roe products using a PCR-based method

Abstract

Fish species identification techniques for authentic food labeling were developed using species-specific PCR primers for cod roe products. A salted, seasoned fish roe product, karashimentaiko (chilli cod roe), is produced from the eggs of Alaska pollock, Theragra chalcogramma, according to the fair trade competition agreement authorized by the Fair Trade Commission of the Japanese government. To examine whether Alaska pollock ovaries or those of other fish species are being used as raw materials for the fish roe products, we developed species identification techniques using PCR amplification of a 255-bp fragment encoding the mitochondrial ATP synthase Fo subunit 6 (ATP6) gene with a species-specific primer set for Alaska pollock mitochondrial DNA. We also designed two species-specific primer sets corresponding to the mitochondrial ATP6 and cytochrome b (cytb) for Gadus spp. and Micromesistius spp. by PCR amplification of 332- and 223-bp fragments, respectively. We examined the species specificity of these PCR-based methods among nine commercially important Gadidae species.