Similar to all other food types, milk and milk products can cause food-borne illness. The quality of milk can be affected by such factors as pathogen contamination and growth, chemical additives, environmental pollution and nutrient degradation.

Microbiological hazards are a major food safety concern in the dairy sector because milk is an ideal medium for the growth of bacteria and other microbes. These can be introduced into the milk from the environment or from the dairy animals themselves. Milk can contain harmful microorganisms such as Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus, Yersinia enterocolitica, Bacillus cereus, Clostridium botulinum, Mycobacterium bovis, Brucella abortus and Brucella melitensis.

Chemical hazards can be unintentionally introduced into milk and milk products, making them unsafe and unsuitable for consumption. Milk can be contaminated when the milking animals consume feed and/or water that contain chemicals. Other causes of contamination may be inadequate control of equipment, the environment and milk storage facilities. Chemical hazards include detergents, teat disinfectants, dairy sanitizers, anti-parasitics, antibiotics, herbicides, pesticides and fungicides.

A zoonosis is an infectious disease that can be transmitted between vertebrate animals and humans. Zoonosis infections commonly associated with the consumption of milk and milk products are tuberculosis, brucellosis, leptospirosis, salmonellosis and listeriosis.