Study shows raw milk cheese aging may not kill H5N1 virus

Study shows raw milk cheese aging may not kill H5N1 virus
Mar 17, 2025
By Farms.com

H5N1 Found in Aged Raw Milk Cheese

Raw milk cheese is known for its unique flavor, but recent research raises concerns about its safety. A study from Cornell University suggests that the required 60-day aging process may not eliminate the H5N1 avian flu virus in raw milk cheese. 

Researchers tested raw milk cheese made from H5N1-spiked milk at various pH levels. The virus remained in cheese aged at pH 6.6 and 5.8 but was inactivated at pH 5.0, the most acidic level. The study also examined real cheddar cheese made from contaminated milk and found the virus present after aging. 

The FDA is currently testing nearly 300 aged raw milk cheese samples for H5N1 contamination. Of 110 collected so far, 96 tested negatives, while results are pending for 14 others. No positive cases have been reported yet. 

Scientists caution that consuming raw dairy products contaminated with H5N1 could increase infection risks. The virus can persist in refrigerated raw milk for up to 56 days, making it a potential food safety hazard. 

In a related development, the New York City Health Department is investigating two cases of H5 avian flu in pet cats. Officials advise pet owners to avoid feeding raw milk or raw food to animals and to limit outdoor exposure. Meanwhile, the USDA has reported new H5N1 cases in backyard poultry flocks in Oklahoma and a live-poultry market in Philadelphia. 

Health authorities continue to assess the risks and reinforce safety measures to prevent H5N1 transmission through contaminated dairy and poultry products. 

Photo Credit: gettyimages-ahavelaar 

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