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

Dairy cows to be tested for bird flu closely
More dairy cows to be tested for bird flu after findings in grocery store milk 02:45

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.

Despite warnings about the health risks of unpasteurized products, The Associated Press reports sales of raw milk appear to be on the rise, citing data from market research firm NielsenIQ. 

Since the bird flu virus was confirmed in U.S. cattle in March, weekly sales of raw cow's milk have ticked up 21% to as much as 65% compared with the same periods a year ago, according to NielsenIQ, whose figures include grocery stores and other retail outlets. 

NielsenIQ's data shows raw milk products still make up only a fraction of overall dairy sales — about 4,100 units of raw cow's milk and about 43,000 units of raw milk cheese were sold the week of May 5, for example, compared with about 66.5 million units of pasteurized cow's milk and about 62 million units of pasteurized cheese.

But raw milk is trending on social media with influencers promoting the unpasteurized product

Mark McAfee, owner of Raw Farm USA in Fresno, California, told AP he can't keep his unpasteurized products in stock.

"People are seeking raw milk like crazy," he said, noting that no bird flu has been detected in his herds or in California. "Anything that the FDA tells our customers to do, they do the opposite."

Donal Bisanzio, senior epidemiologist at nonprofit research institute RTI International says the risk not just for bird flu, but also salmonella, E. coli and other pathogens.

"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," Bisanzio says. "You can have all the nutrients from the (pasteurized) 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 and The Associated Press contributed to this report.

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