LAUSR

Mi-iuy croaker (Miichthys miiuy) is one of the most important ingredients of Korean cuisine and thus has the highest economic value. However, the similar morphological traits among croaker fish belonging to family Sciaenidae are often exploited for seafood fraud. In this study, M. miiuy-specific primer set was designed and further improved by the development of a rapid and cost-effective duplex PCR method. The specificity of M. miiuy-specific duplex PCR was tested using 22 seafood species, and no cross-reactivity was observed. The sensitivity of the PCR assay was found to be 0.1 ng/µL. For the first time, labeling compliance of 43 commercial m-iuy croaker products was verified using both full DNA barcoding and M. miiuy-specific duplex PCR methods. For species identification, BOLDSYSTEMS and GenBank database were screened with the consensus sequences of each PCR product as a query. This identification result was further confirmed using the M. miiuy-specific duplex PCR method. The findings of this study revealed that principal species substituted were law croaker (Pseudotolithus senegallus, n=4), bigeye croaker (Micropogonias megalops, n=3), whitemouth croaker (Micropogonias furnieri, n=1), and tigertoothed croaker (Otolithes ruber, n=1). A significant percentage (21%) of mislabeling was present in commercial mi-iuy products sold on the South Korea market.