Partial changes and an adaption of the slaughter processes of cattle and pigs are necessary, according to new demands of consumer protection (BSE) and the increasing importance of animal welfare during slaughtering for the acceptance of meat as food. The conventional cattle slaughtering process includes some critical stages where a dissemination of Specified Risk Material (SRM: brain, spinal cord) within or onto the carcass and within the slaughterhouse environment can occur. These processes are captive bolt stunning, removal of the head and first of all carcass splitting (sawing the spine lengthways). Captive bolt (CB) stunning results in massive brain tissue damage with bleeding, and in some cases brain tissue also emerges from the CB hole. As the heart is still functioning, there is a risk of brain tissue particles being transferred via the blood flow to heart and lungs or even into the whole carcass. This contamination risk is actually assessed to be low, but a continuing leakage of CNS material from the captive bolt aperture in the further slaughter process may lead to direct and indirect contamination of carcass, meat and equipment. Therefore, alternative stunning methods like electrical stunning or concussion stunning are discussed. A further critical point is the treatment of the head. When the head is removed, the spinal cord is cut with a knife. There is a risk of cross contamination due to spinal protein that may adhere to the knife and because of cerebrospinal fluid, which leaks from the foramen occipitale magnum. Further head cleaning with hand-held hoses following skinning also includes the danger of cross contamination from cleaning water or aerosol. Therefore, measures regarding the safe handling of head and harvesting of head meat are proposed. The most critical point in terms of contamination of the meat surface with SRM is the currently common practice of sawing the spine vertically in the middle with hand-guided belt-type saws. A mixture of sawing residues and rinsing water (,,sawing sludge") collects in the housing of the saw, and if it contains infectious material this leads to contamination of the subsequent carcasses. The most promising methods available at present for minimising this risk appear to be in manual cattle slaughtering boning the entire (not split) carcass, and in industrial cattle slaughtering extraction of the spinal cord by vacuum from the whole carcass followed by conventional sawing or completely sawing out the spine including spinal ganglia. An improvement of animal welfare in pig slaughtering is achieved by driving the animals group-wise to the stunning unit, irreversible stunning methods or otherwise by controlling the efficiency of exsanguination of each single animal. This can be done by measuring the amount of sticking blood per time. A substitution of the stunning gas CO2 by argon/nitrogen is discussed.
