Rapid and simple identification of two closely-related snow crabs (Chionoecetes opilio and C. japonicus) by direct triplex PCR

The snow crab (Chionoecetes opilio) and red snow crab (C. japonicas) are commercially valuable in South Korea, and C. opilio has a higher economic value. However, the similar morphological traits of these two species are often exploited for seafood fraud. In this study, sensitive primer sets specific to C. opilio and C. japonicas were designed, and a species-specific PCR was optimized to identify each crab species in various types of processed food. The specificity of the species-specific PCR was tested using twenty eukaryotic species, and no cross-reactivity was observed. The sensitivity of the PCR assays was found to be 0.005 ng/mu L. Additionally, a direct triplex PCR method, in which rapid DNA extraction was combined with the species-specific PCR, was developed and utilized to differentiate between snow crab and red snow crab from forty-one commercial crab products. This cost-effective and rapid method can be efficiently utilized in various areas, including rapid screening, quality control, and regulatory monitoring, which are important for the food manufacturing industry and regulatory authorities.