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Avoid the contamination of meat with BSE pathogens during slaughtering!
02/2001, 10.01.2001
Experts analyse weak spots and suggest ways of reducing risks
In addition to the safe disposal of risk materials like brain and spinal cord, the conduct of BSE rapid tests for slaughter cattle aged more than 30 months are a first step on the path to greater safety for the consumer in respect of the food, beef. In the opinion of the Federal Agency for Meat Research (BAFF) and BgVV further steps must follow. One such step is the systematic examination of the slaughter process for possible sources of risk. During slaughtering and cutting there is a risk that the meat of healthy (uninfected) animals will be contaminated and will then, in turn, constitute a risk to the consumer. The "critical process steps" in common slaughter practice in Germany have now been jointly analysed by the Federal Agency for Meat Research (BAFF) and BgVV and they have proposed risk-reducing measures.
The conventional form of captive bolt stunning of cattle used in Germany involves a metal bolt penetrating the skull, entering the brain and partially destroying it. Brain particles can be exuded which can then be disseminated through the blood stream and reach the heart and lungs and become embedded there. The federal institutes, therefore, recommend that the heart and lungs of cattle stunned with a captive bolt pistol should not be allowed to enter the food chain and that in future animals should be stunned electrically. The development of corresponding facilities, which are also suited for use in small and medium-sized plants, must be carried forward. The same holds for the development of alternative methods. Initial experiments by BAFF involving the laser stunning of cattle are promising.
Statutory meat inspection stipulates that the head of the animal must also be examined. Prior to this, it is separated with a knife from the rump and cleaned with a shower head. During this process brain and spinal cord may be exuded. The scientists, therefore, recommend that the head should be cleaned in a cabin which is spray-water proof and isolated from the other slaughter carcasses in order to avoid contamination of them.
The lengthwise splitting of the animal carcass in the middle of the spinal column prescribed by the EU is considered to be very high risk as this opens up the vertebral canal and the entire spinal cord is transected. This means that nerve tissue can then contaminate not only the appliances but also adjacent meat parts. BAFF und BgVV suggest that the animal carcasses should not be split in two until reliable methods are available to completely remove the spinal cord and/or the unsplit spinal column on the evisceration line.
In principle, all objects which come into contact with risk material are to be considered contaminated. This applies in particular to work appliances which are used to remove or cut risk material. They may only be used for the respective purpose and must be properly decontaminated. The interim disinfection envisaged already now with hot water and final disinfection must be retained for hygienic reasons. These measures are not, however, sufficient to inactivate BSE pathogens. If a slaughter animal proves to be BSE positive in the BSE rapid test, special measures to remove any possible infectious material must be taken in addition to the cleaning and disinfection to be carried out regularly at the end of the working day. Meat from animals slaughtered in the same evisceration line after an animal which tested positive or not clearly negative in the rapid test prior to cleaning, may not be placed on the market but must be disposed of in a safe manner. As the result of a rapid test is not normally available until the day after slaughtering, all animals slaughtered on the previous day may be affected by this measure.