OBJECTIVETo study influencing factors of detection of bovine central nervous system (CNS) tissue contaminated beef by enzyme immunoassay (EIA), and the method was applied to the detection of imported beef and domestic beef of China.

METHODSRaw beef homogenates containing different concentrations of raw CNS tissue and the same samples which were heated were detected after different time by RIDASCREEN(r) Risk Material 10/5 and RIDASCREEN(r) Probennahme- zubehor Sampling tools kits. PBS suspension and sample dilution buffer (SDB) suspension of bovine brain tissue with the same concentration of the standard were detected. Beef from USA and domestic market of China were then detected by the kits.

RESULTSThe kits could detect both raw and heated CNS tissue in the products with high sensitivity. The absorbance values (AV) increased with the concentrations of CNS in samples. Heating and increasing of time could decrease the absorbance values of the samples which contain CNS tissue. The AV of the PBS suspension of bovine brain tissue was higher than the SDB suspension and the AV of both were higher than the AV of standard of the same concentration. No CNS tissue was detected from all imported beef. No CNS tissue was detected in all samples from domestic market of China except for foxtail.

CONCLUSIONThe EIA method has high sensitivity for detection of bovine CNS tissue contaminated beef with the glial fibrillary acidic protein (GFAP) as accurate target substance. Heating and increasing of time can lead to decreasing of the AV of samples. Improper slaughter process can lead to contamination of bovine products by bovine CNS tissue.