Colorado State University Extension
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SAFETY CONCERNS ABOUT RAW MILK
Edited by: Stephanie Wallner, M.S., Mary Schroeder, M.S., R.D, Pat Kendall, Ph.D., R.D., Colorado State - Winter 2007
For many, milk is an important source of nutrients and a regular part of the daily diet. Because raw milk naturally contains bacteria, some of which may be pathogenic, most of the milk we drink is pasteurized for safety. In recent years, however, there has been increasing interest in raw milk among some consumers due to supposed beneficial health claims made by raw milk advocates. Proponents of raw milk suggest that pasteurization destroys nutrients, enzymes that facilitate calcium absorption, and beneficial bacteria present in milk. They also claim that pasteurized milk is associated with or even causes allergies. The website RawMilk.org, which serves supporters of raw milk, suggests that pasteurization alters and destroys proteins, vitamins, minerals, enzymes and other nutrients, and that toxins are formed in their place. As for the benefits of raw milk, advocates claim that it promotes calm nerves, eliminates poisons and toxins from the body, reverses malnutrition, and promotes overall good health, among other effects. However, the Food and Drug Administration (FDA) maintains that drinking raw milk is dangerous and can cause serious foodborne illness.
Raw milk and other milk-based products naturally contain both beneficial and pathogenic bacteria. The harmless bacteria, such as Lactobacillus, help produce yogurt and other dairy foods and have a role in promoting gastrointestinal health. Unfortunately, milk also may contain pathogenic or harmful bacteria such as Listeria monocytogenes, Campylobacter jejuni, E. coli O157:H7, and Salmonella. These bacteria can be shed by animals into milk at the farm, and since milk is a nutritionally complete substance, it becomes an ideal environment for bacterial growth. Infections from these pathogenic bacteria, especially in persons with compromised immune systems, can cause severe diarrhea, cramps, fever, nausea, vomiting, headache, and dehydration. Infections in children, the elderly, and others with compromised immunity can be particularly severe and can lead to complications such as hemolytic uremic syndrome.
Because of the dangers of pathogenic bacteria, most milk is treated by pasteurization, which was originally developed to kill the bacterium that causes tuberculosis. Pasteurization is a heat treatment used to kill harmful bacteria and bacteria that cause spoilage without changing the milk's nutritional content, flavor, or quality. Pasteurization kills bacteria that cause tuberculosis as well as salmonellosis, diphtheria, typhoid fever, and other illnesses. Following production and packaging, rapid cooling of the milk and storage below 40 degrees F help prevent milk spoilage and keep treated milk safe to drink. Despite the claims of raw milk advocates, the FDA and other public health agencies have stated that there is no known significant nutritional difference between unpasteurized and pasteurized milk, and that treated milk still provides the nutrients found naturally in raw milk. According to the FDA, the benefits of killing harmful bacteria outweigh any health benefits claimed by raw milk advocates, and recent outbreaks of foodborne illness associated with untreated milk have helped to renew public awareness of the dangers of raw milk consumption.
In a 2002-2003 outbreak of Salmonella Typhimurium, 62 people in Illinois, Indiana, Ohio and Tennessee became ill after consuming raw milk sold in Ohio. The milk producer linked to the outbreak later relinquished its license for raw milk sales following a recommendation from the Ohio Department of Agriculture. In Washington state, an outbreak of E. coli O157:H7 infection in late 2005 was linked to raw milk and caused serious illness in eight people, several of whom were hospitalized. Washington State health authorities linked the outbreak to locally sold raw milk and ordered the unlicensed provider of the milk to close. In another case, five people became ill with Campylobacter infection in early 2005 after drinking raw milk linked to a dairy in Larimer County, Colorado. The direct sale of raw milk is illegal in Colorado, but consumers may still buy shares in dairy cows. Raw milk from a shared cow likely caused the 2005 outbreak, according to the Colorado Department of Public Health and Environment.
In cases such as these, raw milk can cause severe illness and related complications, especially for individuals with compromised immune systems. However, there are regulations in place to protect consumers from the dangers of raw milk. At the federal level, the FDA provides regulation for the treatment and processing of raw milk into pasteurized milk and other dairy products through the National Conference on Interstate Milk Shipments "Grade A" program. This program, a cooperative effort between the FDA and all 50 states, helps to regulate standard milk regulations and milk safety. The FDA's related code of regulations is listed in the Pasteurized Milk Ordinance, or PMO, which states can adopt individually for their own policies. As part of the "Grade A" program, farms and products must undergo inspections and are assigned ratings by state and FDA personnel.
In addition, federal law requires that milk shipped across state lines for sale at retail stores must be pasteurized. However, within each state, regulations are up to local governments, and some states allow raw milk to be sold. In some states like Colorado, where the sale of raw milk is illegal, consumers can get around the law by "cow sharing" - group members pay a fee to a farmer to purchase a cow and use the raw milk. Other states, like Wisconsin, have banned cow sharing following an outbreak of Campylobacter infection linked to raw milk from cow sharing.
Despite the possible health benefits touted by raw milk advocates, the FDA and other public health officials advise consumers to avoid drinking beverages or eating foods made with unpasteurized milk, including raw milk soft cheeses from any source. It is especially important for persons with reduced immunity - the young and elderly, pregnant women, or those with diseases that compromise immune function - to avoid raw milk products and to have the best information available regarding the risks of raw milk.
Sources:
- Articles posted on http://www.rawmilk.org, December 2006.
- Sheehan, J.F. (2005). On the Safety of Raw Milk (with a word about pasteurization). United States Food and Drug Administration (FDA) website, available at: http://www.cfsan.fda.gov/~ear/milksafe.html.
- Cornell University Dairy Science Factsheet. Why pasteurize? The dangers of consuming raw milk. Department of Food Science, Cornell University, Ithaca, NY, 2002.
- United States Food and Drug Administration. Got Milk? Make Sure It's Pasteurized. FDA Consumer Magazine, 38(5), Sept-Oct 2004. Available at: http://www.fda.gov/fdac/features/2004/504_milk.html.
- Multistate outbreak of Salmonella serotype Typhimurium infections associated with drinking unpasteurized milk - Illinois, Indiana, Ohio, and Tenn, 2002-2003. MMWR 2003: 52(26); 613-615.
- Washington State Department of Health website. E. coli Outbreak in Southwestern Washington Highlights Risks of Raw Milk. Available at: http://www.doh.wa.gov/Publicat/2005_news/05-164.htm.
- "Raw milk sickens five: Larimer dairy implicated." The Daily Reporter-Herald, Loveland, CO. January 21, 2006.
