The inner flesh of meats of poultry and fish from healthy, farm-raised animals contain few or no micro-organisms, although they may be present in other parts of the carcass. Contamination can occur, however, during slaughtering, handling and processing. The practices of intensive animal husbandry have introduced potential new risks, such as infections and drug residues.
Diseased animals and animals with visible tumours and abscesses are routinely processed and eaten, although often the offending limb or organ has been removed. For example, cattle suffering from brucellosis are considered safe for consumption in most countries unless the disease was especially acute, so long as the udder and uterus were removed first. Whole carcasses with tumours are only condemned if they are malignant with secondary growths or multiple growths.
Bovine spongiform encephalopathy (BSE), scrapie and Creutzfeldt Jakob disease (CJD) are different forms of the same syndrome in cattle, sheep and humans, respectively. The disease causes irreversible damage to the brain and spinal cord. BSE first appeared in the UK in 1986, in cattle that were fed recycled sheeps brains infected with scrapie. The UK Ministry of Agriculture claims that infections cannot be transmitted from animals to humans by eating red meat. Infected cattle brain and spinal cord routinely went into sausages, pies, stock cubes, and patés in the UK between 1986 and 1989, when a ban on putting suspected offals into human food was imposed. Calves' brains are still permitted to be used in such preparations. Whilst CJD is regarded as a rare disease of the aged, there are two known cases in young women in the UK, both meat eaters, and two recent deaths of dairy farmers.
In the UK during the 1970s and 1980s cattle with brucellosis were eaten and their pasteurised milk was drunk without any proven evidence of a rise in undulant fever.