Most Dairy-Linked Disease Tied to Raw Milk

Unpasteurized milk blamed for disease outbreaks

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(RxWiki News) Among dairy-related disease outbreaks, raw milk appears to be the culprit. In states where the sale of unpasteurized milk is legal, the number of outbreaks doubles.

A recent U.S. Centers for Disease Control and Prevention study also found that raw milk and products made from it caused 150 times more outbreaks than the number linked to pasteurized milk even though raw milk accounts for only 1 percent of milk consumed in the U.S.

"Only drink milk that is pasteurized."

During pasteurization, milk is heated to kill bacteria. However, this step does not occur when raw milk is collected, and multiplying bacteria can cause illness.

Dr. Robert Tauxe, deputy director of CDC’s Division of Foodborne, Waterborne and Environmental Diseases, noted that the research identified a link between state laws and the number of outbreaks or illnesses from raw milk.

He said that restricting the sale of raw milk products could help reduce the annual number of outbreaks and keep individuals healthier. States that continue to allow the sale of unpasteurized milk are likely to continue to see outbreaks, Dr. Tauxe said.

During the 13-year review investigators reviewed dairy product outbreaks between 1993 and 2006 in all 50 states. This includes outbreaks linked to cheese and yogurt.

Researchers compared the amount of milk produced in the U.S. during that period -- about 2.7 trillion pounds -- against the amount the CDC estimates was consumed raw. CDC officials estimate about 27 million pounds, or 1 percent of milk, is consumed raw.

CDC investigators reviewed 121 dairy-related disease outbreaks that caused 4,413 illnesses, 239 hospitalizations and three deaths. Raw milk was blamed in 60 percent of those cases. Most hospitalizations -- 200 out of 239 -- were also caused by raw milk.

In addition, 13 percent of those sickened in raw milk outbreaks were hospitalized compared to 1 percent who drank pasteurized milk. Investigators suspect this is because raw milk is linked to more severe illnesses caused by bacteria such as E. coli, while pasteurized milk illnesses were associated with milder infections such as norovirus and Staphylococcus aureus.

Raw milk-linked illnesses also disproportionately affected those under age 20, with 60 percent of raw milk patients younger than age 20 as compared to 23 percent who drank pasteurized milk. Bacteria in raw milk tends to cause more serious illness in children as compared to adults.

“While some people think that raw milk has more health benefits than pasteurized milk, this study shows that raw milk has great risks, especially for children, who experience more severe illnesses if they get sick,” said study co-author Dr. Barbara Mahon, deputy chief of CDC’s DFWED Enteric Diseases Epidemiology Branch. “Parents who have lived through the experience of watching their child fight for their life after drinking raw milk now say that it’s just not worth the risk.”

The outbreaks occurred in 30 states, with 75 percent of outbreaks occurring in the 21 states where it was legal to sell unpasteurized milk.

The study was published in the Feb. 21 issue of CDC journal Emerging Infectious Diseases.

Last Updated:
February 22, 2012