June 6, 2006
National Center for Infectious Diseases
Each year, people become ill from drinking raw milk and eating foods made from raw dairy products. Unlike most of the milk, cheese, and dairy products sold in the United States, raw milk and raw dairy products have not been heat treated or pasteurized to kill germs. Although many states outlaw the sale of these items, many people including dairy producers, farm workers and their families, and some ethnic groups continue to drink raw milk and eat foods made from raw dairy products. Several types of raw cheeses such as feta, brie, queso fresco, sheep’s and goat’s milk cheese have been illegally sold in the United States.
Germs in These Products Cause Thousands of Illnesses
Raw milk and raw dairy products may carry many types of disease-causing germs such as Campylobacter, Escherichia coli, Listeria, Salmonella, Yersinia, and Brucella. When raw milk or raw milk products become contaminated, people who eat the contaminated foods can get sick. Here are a few examples of outbreaks that have been reported since 2000:
2001: Outbreak of Campylobacter jejuni infections from drinking “raw” or unpasteurized milk.
2003: Outbreak of Listeria monocytogenes infections from eating unpasteurized queso fresco (a Mexican-style soft cheese)
2003: Outbreak of Salmonella infections from eating unpasteurized queso fresco.
2004: Outbreak of E. coli.O157 infections from eating unpasteurized queso fresco
These Illnesses Can Be Dangerous
Getting sick from one of these germs can lead to diarrhea, stomach cramps, fever, headache, vomiting, or exhaustion. The misery typically lasts anywhere from several hours to a week or more but most healthy people will recover.
These illnesses can be dangerous for people with weakened immune systems, such as the elderly, children, and people with cancer, an organ transplant, or HIV/AIDS. Germs found in raw milk and raw dairy products can be especially dangerous to pregnant women and their unborn babies.
Pasteurization Is Key to Making Dairy Products Safe
Heat-treating milk to kill germs is called pasteurization . Using heat to pasteurize milk was first suggested in the late 1800’s as a way to decrease the amount of a germ that causes tuberculosis. Today, pasteurization is still our main protection from germs carried in milk and cheese.
Pasteurization is a simple process. In the United States, raw milk is collected from cows and heated to a high temperature for a short period of time. This destroys any harmful germs that may be contaminating the milk. After it is pasteurized, milk and products made from milk are safe for human consumption. Pasteurization does not harm the nutritional value of milk and cheese.
Playing It Safe
When shopping for milk or cheese, play it safe. Carefully read food labels to make sure a product is pasteurized. Purchase only products that are pasteurized or made from pasteurized milk.
These people should always avoid raw milk or raw dairy products:
Pregnant women or women considering pregnancy
Children under 5 years of age
Persons infected with HIV
Persons with cancer
Anyone who is immunocompromised (such as persons with organ transplants)