Real-time PCR assays for detection and quantitation of porcine and bovine DNA in gelatin mixtures and gelatin capsules

Abstract

Detection and quantitation of material from porcine and bovine species in gelatin and gelatin capsules is required for health safety concerns and for some religious practices. In this study, two species-specific qPCR assays were developed based upon repetitive elements. They allowed sensitive detection of porcine and bovine DNA at as low as 1pg/mL. The lack of cross-reactivity when the sets were used to amplify DNA from the other species indicates high specificity of the assay. When binary gelatin blends containing various amounts of porcine and bovine gelatin were prepared and analyzed by the qPCR assays, the determined ratios of porcine material to bovine material were very close to their theoretical values, and a contamination level as low as 1% of the other species in the gelatin blends could be determined. When evaluated in gelatin capsules, although significantly less DNA was detected, determination of porcine and bovine species identities and estimation of the relative abundance of each species was possible. Therefore, the porcine and bovine species-specific qPCR assays described here represent simple, reliable and sensitive DNA-based tests for determination and quantitation of the species of origin from highly processed products.