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Shortly after the identification of Bovine Spongiform Encephalopathy (BSE) in cattle, concerns emerged that this disease could be transmitted to humans consuming meat or meat products. Such concerns have been exacerbated by confirmation that the infectious agent, a prion isolated from BSE-infected cattle, shares a number of characteristic biological and structural features with the infectious agent of variant Creutzfeldt-Jacob disease (vCJD) in humans.
Particular risks are associated with those elements of the bovine central nervous system (CNS), which are most closely linked with BSE i.e. the brain and the spinal cord, and their potential for contamination of carcass meat, abattoir workers and environment during the slaughter of BSE-infected animals. Current practices in stunning, slaughter and butchery of cattle may allow brain and/or spinal cord tissue to contaminate carcass and enter the food chain. If such carcasses are consumed by humans this may lead to the development of vCJD. Up to date, in comparison to the reported 143 definite or probable vCJD cases in the UK, the identified cases in the Mediterranean countries were quite low; 6 in France, and one in Italy.
Nevertheless, we still do not know the incubation period of the vCJD, the susceptibility of other than methionine homozygous individuals, the possibility of other strains of BSE to be existed, the cause of the steady increase in the incidence of the sporadic Creutzfeldt-Jacob disease in certain countries and the implications of possible co-existence of BSE and scrapie in sheep.
As far as the confirmed BSE cases in the Mediterranean countries are concerned a decline in France and Italy, stabilization in Portugal, and an increase in Spain during the last few years has been observed. It is necessary to derive alternative and/or additional means of preventing and/or minimizing such frequent and wide release of CNS material during slaughter. Such methods are discussed. The replacement of the penetrative stunning method with the cardiac arrest stunning, in regions where the BSE is present, will prevent the risk of dissemination of brain particles into the blood and carcass. Alternative methods of spinal column/cord removal reducing the contamination of carcass and/or environment must be employed.
The changing of the entire slaughter process in order to minimize the risk of CNS contamination of the carcass, operatives and abattoir equipment and environment should be taken into serious consideration. |
