[show abstract][hide abstract] ABSTRACT: The removal of certain central nervous system (CNS) tissues (part of the bovine spongiform encephalopathy risk material) from the food chain is one of the highest priority tasks associated with avoiding contamination of the human food chain with the agent of bovine spongiform encephalopathy. A recently developed real-time PCR assay and three commercially available enzyme-linked immunosorbent assays (ELISAs) for the detection of CNS tissues in minced meat and three types of heat-treated sausages were evaluated. Bovine brain was used for spiking of internal reference material, and its detectability was examined during storage times of 12 months (for frozen minced meat and liver sausage) and 24 months (for sausages treated with medium and high heat). The real-time PCR method and both ELISA kits detected 0.1% CNS tissue in frozen minced meat and 0.1 or 1% CNS tissue in heat-treated meat products. The detectability of the amplified mRNA target region with the PCR assay was similar to the detectability of antigen by the ELISAs. Because the real-time PCR method also can be used to distinguish cattle, ovine, and caprine CNS tissues from porcine CNS tissues, it seems to be suitable as a routine diagnostic test for the sensitive and specific detection of CNS tissues in meat and meat products.
Journal of food protection 11/2008; 71(10):2059-66. · 1.83 Impact Factor
[show abstract][hide abstract] ABSTRACT: Several phenotypic as well as genotypic methods have been published describing the detection of central nervous system (CNS) tissues that are part of the bovine spongiform encephalopathy (BSE) risk material in food products. However, none of these methods is able to differentiate between CNS tissue of the banned ruminant species and tissues of other animal species. A quantitative and species-specific real-time RT-PCR method has been developed that enables the reliable identification of CNS tissues in meat and meat products. This method is based on a messenger (m)RNA assay that uses bovine, ovine and caprine glial fibrillary acidic protein (GFAP) encoding gene sequences as markers. The in-house validation studies evaluated the tissue specificity of up to 15 bovine tissues and the standardization of absolute as well as relative quantitative measurement. The specific amplification of spinal cord and brain tissue GFAP cDNA has been shown previously. In addition, two commercially available ELISA kits were used for the comparative analysis of artificially contaminated minced meat. Small quantities of bovine brain that had been stored over the recommended period of 14 days were examined. The real-time PCR method proved to be suitable for the detection of 0.1% CNS tissue. No false negative results were observed. The quantitative detection of GFAP mRNA using real-time RT-PCR seems a suitable tool in routine diagnostic testing that assesses the illegal use of CNS tissue in meat and meat products. The stability of the selected target region of the GFAP mRNA also allows the detection of CNS tissues after the meat has been processed.