E. coli O157:H7 causes an estimated 73,000 illnesses and 61 deaths annually in the United States (2). Approximately 8% of reported infections lead to HUS [ie kidney failure], particularly in children aged <5 years and older adults (3); 4% of patients with HUS die (4). Raw milk is an important vehicle of transmission of E. coli O157:H7 and other pathogens, including Mycobacterium bovis, Listeria monocytogenes, and Campylobacter, Brucella, and Salmonella species (5,6). During 1988--2005, a total of 33 outbreaks of Campylobacter species, E. coli O157:H7, and Salmonella species infections associated with raw milk consumption were reported to CDC (7).
Although many consumers are aware that raw milk can contain pathogens, some believe that it has potential benefits (e.g., vitamins that are present naturally rather than added, enhanced fertility, and protection against tooth decay). However, the validity of any health or nutritional benefits from consuming raw milk has not been proven scientifically (6).
Raw milk is a well-documented cause of enteric infections and was first recognized as one approximately 100 years ago (6). Pathogens that infect humans, including E. coli O157:H7, are shed in the feces of cows and can contaminate milk during the milking process. Using standard hygiene practices during milking (e.g., washing hands, keeping equipment clean, and keeping the milking area separated from other areas) can reduce but not eliminate the risk for milk contamination. Pasteurization decreases the number of pathogenic organisms, prevents transmission of pathogens, and has been determined to improve the safety of raw milk more than other measures, including certification of raw milk (8). Because raw milk certification has failed to prevent many raw-milk--associated infections in the past, consumers should not assume that certified raw milk is free of pathogens (9). To prevent E. coli O157:H7 and other infections, consumers should not drink raw milk.
Early in the 20th century, widespread adoption of the pasteurization process led to substantial reductions in milk-associated disease, a milestone in the history of food safety (10). In the 21st century, more effective consumer education regarding the hazards of drinking raw milk is needed to further reduce milk-associated diseases.