Escherichia coli can colonize the intestines of animals, which could contaminate muscle meat at slaughter. These organisms do not normally cause any harm. However, there are rare strains such as E. coli O157:H7, which produces large quantities of a potent toxin that forms in and causes severe damage to the lining of the intestine. The resulting disease is called Haemorrhagic Colitis and is characterized by bloody diarrhoea. E. coli O157:H7 is easily destroyed by thorough cooking.

Salmonella may be found occasionally in the intestinal tracts of livestock, poultry, dogs, cats, and many other animals. At slaughter the meat may become contaminated and thus refrigeration is needed to prevent multiplication. Freezing doesn't kill this microorganism, but thorough cooking destroys it. Cross-contamination can occur if raw meat and/or its juices are in contact with cooked food or foods that will be eaten raw, such as salad. Salmonella causes gastroenteritis, i.e. diarrhoea.

Staphylococcus aureus is present on the hide of cattle but is also carried on human hands, nasal passages, or throats. Most foodborne illness outbreaks are a result of contamination from food handlers and production of a heat-stable toxin in the food after temperature abuse; exceptionally, sausages that have not been properly fermented may cause illness, mainly acute vomiting followed by diarrhoea. Good manufacturing practices, hygienic food handling and refrigerating should prevent staphylococcal foodborne illness.

Listeria monocytogenes is found in the intestines and milk of cattle. Even though cooking destroys this organism, poor handling practices can recontaminate a cooked product and growth can occur even at refrigeration temperatures. Cooked and ready-to-eat products such as frankfurters and luncheon meat should not be kept too long in refrigerators. Observe handling information such as "Keep Refrigerated" and "Use-By" dates on labels.