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
Elk bacterial disease brucellosis occasionally affects elk in the Greater Yellowstone Ecosystem, the only place in the U.S. where the disease is still known to exist. In domesticated cattle, brucellosis causes infertility, abortions and reduced milk production. It is transmitted to humans as undulant fever, producing flu-like symptoms which may last for years. Though bison are more likely to transmit the disease to other animals, elk inadvertently transmitted brucellosis to horses in Wyoming and cattle in Idaho. Researchers are attempting to eradicate the disease through vaccinations and herd management measures, which are expected to be successful. Nevetheless, research has been ongoing