Raw milk is milk that has not been pasteurized or homogenized.

History

Humans consumed raw milk exclusively prior to the industrial revolution and the discovery of the pasteurization process in 1864. During the industrial revolution large populations congregated into urban areas detached from the agricultural lifestyle. Up until that point, individuals and families owned their own goats, cows, and other livestock and milked them on a daily basis.

Pasteurization was first used in the United States in the 1890s after the discovery of germ theory to control the hazards of highly contagious bacterial diseases including bovine tuberculosis and brucellosis that was thought to be easily transmitted to humans through the drinking of raw milk. Initially after the scientific discovery of bacteria, no product testing was available to determine if a farmer's milk was safe or infected, so all milk was treated as potentially contagious. After the first test was developed, some farmers actively worked to prevent their infected animals from being killed and removed from food production, or would falsify the test results so that their animals would appear to be free of infection.

When it was first used, pasteurization was thought to make raw milk from any source safer to consume. More recently, farm sanitation has greatly improved and effective testing has been developed for bovine tuberculosis and other diseases, making other approaches to ensuring safety of milk more feasible; however pasteurization continues to be widely used to prevent infected milk from entering the food supply.