Viral Bird Flu Detected in U.S. Milk Samples, Indicating Wider Spread Among Dairy Herds

The U.S. Food and Drug Administration (FDA) has detected fragments of the bird flu virus in samples of pasteurized milk purchased from retail grocery stores across the country.

While the agency maintains that the milk is safe to drink, the findings suggest that the outbreak of the H5N1 bird flu virus in dairy cows is more widespread than previously known.

The FDA confirmed the presence of viral particles in some milk samples but stated that pasteurization typically inactivates pathogens, though it does not remove genetic material.

The agency is conducting additional tests to determine if the virus remains infectious. "The FDA believes the milk is still safe to drink, as the viral particles are likely remnants of viruses killed during the pasteurization process," an FDA spokesperson said.

Why this matters: The detection of bird flu in the U.S. milk supply raises concerns about the potential for the virus to spread further and mutate, which could lead to human infections. Health officials are closely monitoring the situation to prevent a possible pandemic.

Over the last month, the highly pathogenic avian influenza virus has been detected in more than 30 dairy herds across eight states. The U.S. Department of Agriculture (USDA) had previously confirmed the presence of the virus in dairy cows but the extent of the outbreak appears to be greater than reported.

Experts believe the outbreak is more widespread than the USDA data indicates and have expressed concerns about the lack of transparency and data-sharing from the agency. "There has been a scarcity of information from the USDA, and more data is needed to fully understand what's going on with the current bird flu virus in dairy cows," said Michael Osterholm, an infectious disease expert.

The bird flu virus has caused mass deaths in wild bird populations and infected other animals, including sea lions in South America. While the virus has a high mortality rate, to date only two human cases have been reported in the U.S. during the current outbreak, with both individuals experiencing mild symptoms and fully recovering.

The FDA and USDA have reiterated that the commercial milk supply remains safe due to pasteurization and the diversion or destruction of milk from infected cows. Nearly 99% of U.S. milk farms follow the FDA's pasteurization ordinances, which are expected to effectively inactivate heat-sensitive viruses like H5N1.

The FDA, CDC, and USDA are collaborating to investigate the outbreak and assess the effectiveness of pasteurization in killing the bird flu virus in milk. "The established pasteurization process set forth in the Pasteurized Milk Ordinance is expected to effectively inactivate heat-sensitive viruses like H5N1 in milk," the FDA stated. Additional test results are expected in the coming days and weeks to provide more updates on the situation.

Key Takeaways

• The FDA detected bird flu virus fragments in pasteurized retail milk samples.
• Pasteurization inactivates pathogens, but genetic material may remain.
• the outbreak in dairy cows is more widespread than previously reported.
• Experts are concerned about a lack of transparency from USDA on outbreak data.
• FDA, CDC, USDA investigating effectiveness of pasteurization against H5N1.