United States raw milk debate systematic review of the food safety of unpasteurized milk concluded that science-based data to substantiate claims of health benefits "are lacking or do not exist" and the risks associated with disease outbreaks as a result of raw milk consumption are "considerably higher". 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 could 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
Milk via ultra filtration, which removes smaller molecules such as lactose and water while leaving calcium and proteins behind. Milk produced via these methods has a lower sugar content than regular milk. In areas where the cattle (and often the people) live indoors, commercially sold milk commonly has vitamin D added to it to make up for lack of exposure to UVB radiation. Reduced-fat milks often have added vitamin A palmitate to compensate for the loss of the vitamin during fat removal; in the United States this results in reduced fat milks having a higher vitamin A content than whole milk.