Detection of bovine central nervous system tissue as bovine spongiform encephalopathy risk material by real-time reverse transcriptase-PCR in raw and cooked beef products

There is increasing evidence of the association of the new variant of Creutzfeldt-Jacob disease (nvCJD) in humans with bovine spongiform encephalopathy (BSE) in cattle. Many countries established legislation of banning central nervous system (CNS) tissues, which are regarded as BSE-specified risk materials (SRM), in human food supply because of the potential transmission of BSE to humans. A real-time reverse transcriptase-PCR assay using the bovine glial fibrillary acidic protein (GFAP) mRNA template for the detection of CNS tissues in raw and cooked beef products was developed in this study. The results showed that (1) this method can detect CNS tissues from bovine and ovine origins, but not from porcine and avian ones; (2) GFAP mRNA can only be detected from brain and spinal cords rather than other tissues; (3) the GFAP mRNA was detectable in CNS tissues even after dilution to 0.001%; and (4) the assay was unaffected by heat treatment at 100 degrees C for 30 min or storage at room temperature for 4 days, and at 4 degrees C for at least 15 days.