Bird flu risk prompts warnings against raw milk, unpasteurized dairy products

Pasteurization is working to kill off bird flu in milk, according to tests run by the Food and Drug Administration — but what about unpasteurized dairy products like raw milk? Experts advise to stay away, especially with the recent avian influenza outbreak affecting growing numbers of poultry and dairy cows. 

"Do not consume unpasteurized dairy products," Dr. Nidhi Kumar told CBS New York. "I know there are people that are real advocates for it, but this is not the time to do it."

The Centers for Disease Control and Prevention calls raw milk "one of the riskiest foods."

"Raw milk is milk that has not been pasteurized to kill harmful bacteria," the health agency's website explains. "Raw milk can be contaminated with harmful germs that can make you very sick." The CDC says raw milk can cause a number of different foodborne illnesses, and people might experience days of diarrhea, stomach cramping and vomiting.

"It's not just about bird flu, it's about salmonella, E. coli (and more pathogens)," says Donal Bisanzio, senior epidemiologist at nonprofit research institute RTI International. "A lot of people they think the pasteurization can reduce, for example, the quality of the milk, but no one really has shown something like that. ... You can have all the nutrients from the (pasteurized) milk."

Bisanzio says only about 1% of people in the U.S. drink raw milk.

It is not yet known if the bird flu virus can pass through raw milk to humans, Bisanzio says — but if it can, he expects symptoms to be similar to other modes of contraction. 

"(If) the amount of virus in the raw milk is enough to infect a human being, you're going to expect the same kind of symptoms — flu-like symptoms like fever, nausea — that you can find in people that are affected by an infection through other different routes."

The FDA's findings for pasteurized milk come after the agency disclosed that around 1 in 5 samples of retail milk it had surveyed from around the country had tested positive for highly pathogenic avian influenza, or HPAI H5N1. The additional testing detected no live, infectious virus, reaffirming the FDA's assessment that the "commercial milk supply is safe," the agency said in a statement.

-Alexander Tin contributed to this report.

In:
• Bird Flu

Sara Moniuszko

Sara Moniuszko is a health and lifestyle reporter at CBSNews.com. Previously, she wrote for USA Today, where she was selected to help launch the newspaper's wellness vertical. She now covers breaking and trending news for CBS News' HealthWatch.

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