Control points to reduce movement of central nervous system tissue during beef slaughter
Citation
Aalhus, J.L., Thacker, R.D., Larsen, I.L., Roberts, J.C., Price, M.A., Juárez, M. (2017). Control points to reduce movement of central nervous system tissue during beef slaughter, 80(2), 355-360. http://dx.doi.org/10.4315/0362-028X.JFP-16-302
Plain language summary
Specified risk materials (SRM) are the tissues from cattle carcasses which are most likely to contain bovine spongiform encephalopathy (BSE) or “mad-cow disease” causing prions; in BSE infected cattle, specified risk materials contain more than 99% BSE infectivity. Tissues identified as specified risk materials include brain, spinal cord, trigeminal and dorsal root ganglia, eyes, and tonsils in animals older than 30 months of age and the intestine in cattle of all ages. Abattoir procedures must be designed to safely remove SRM from the carcasses and limit the spread of SRM during the slaughter and dressing procedures. The aim of this study was to evaluate the spread of SRM during different points in the slaughter and dressing procedure. The spread of SRM was measured by analyzing the concentration of a protein (glial fibrillary acidic protein), which is found in many SRM, from swabs samples obtained on different regions of the carcasses and from abattoir equipment. During slaughter, use of a plug inserted into the cranium immediately following captive-bolt stunning reduced the spread of SRM in the area surrounding the stun site. Carcass splitting with a conventional splitting band saw resulted in increased SRM spread in various regions of the carcass. Rinsing carcass sides in hot water (84°C) effectively reduced the SRM present on the carcass in most regions to a greater extent than rinsing in cold water with similar water pressure. Finally, several pieces of abattoir equipment and regions in the abattoir such as: the base of the splitting band saw blade, the floor below the spltting band saw station, the aprons worn by meat processing staff, and the brush used to mark the spinal column all had SRM present after use on the kill floor. The presence of SRM on abattoir equipment reinforced the need to use adequate sanitation procedures. The results of this study present evidence that use of a plastic plug in the stun site and hot water rinsing can help reduce the spread of SRM on cattle carcasses.
Abstract
© 2017 International Association for Food Protection. Consumption of central nervous system tissue (CNST) from cattle with bovine spongiform encephalopathy (BSE) is thought to cause the human neurological disease, variant Creutzfeldt-Jacob disease. To identify points of cross-contamination of beef carcasses with CNST, 55 young beef cattle were slaughtered and processed through a federally inspected multispecies abattoir. The objectives of this study were to evaluate CNST spread following the placement of a plug in the penetration site of the skull after captive bolt stunning, to evaluate cross-contamination of carcasses before and after splitting, to compare the effects of hot water pasteurization (84°C for 10 s) versus cold water wash (10°C for 30 s) for reducing CNST on the carcass, and to examine other possible sources of cross-contamination in the abattoir. Results indicated that the use of a plastic plug reduced CNST contamination near the bolt penetration site. This study also confirmed that carcass splitting resulted in an increase in CNST contamination at various areas of the carcass. Hot water pasteurization appeared to be an effective means of removing CNST contamination from carcasses in most of the areas sampled.