Development of detection method for edible silkworm (Bombyx mori) using real-time PCR

The consumption of silkworms as edible insects has recently increased because of their good nutrition content. Many insect-based products are processed into a powder because of their unappetizing appearance. In this aspect, powdered silkworm has the possibility to be mixed with other insects. Thus, the development of a detection method for silkworm is necessary to provide accurate label information to consumers. In this study, we developed a real-time PCR assay using a TaqMan probe for detection of silkworm. The newly designed silkworm-specific primer pair and probe target the mitochondrial cytochrome oxidase subunit I (COI) gene. They were tested for their specificity using 15 insect species, and were confirmed to amplify only silkworm species. The limit of detection of this method was 0.001 ng of silkworm DNA, and as little as 1% of silkworm in two or more insect mixtures was detected. This developed method was applied to 30 processed foods including edible insects and was validated with four different real-time instruments. Therefore, the silkworm-specific real-time PCR assay may provide a specific and sensitive method for detection of silkworm in raw and processed foods.