The U.S. government said on Monday it is collecting ground beef samples at retail stores in states with outbreaks of bird flu in dairy cows for testing but remains confident the meat supply is safe.
Federal officials are seeking to verify the safety of milk and meat after confirming the H5N1 virus in 34 dairy cattle herds in nine states and one person in Texas since late March.
Both the Centers for Disease Control and Prevention and the World Health Organization have said the overall public health risk is low, but it is higher for those exposed to infected animals.
Scientists believe outbreaks are more widespread in cows than officially reported based on findings of H5N1 particles in about 20% of milk samples.
The U.S. Food and Drug Administration said on Friday that preliminary results of gold-standard PCR tests showed that pasteurization killed the bird flu virus in milk.
The U.S. Department of Agriculture will analyze retail ground beef samples with PCR tests that indicate “whether any viral particles are present,” according to a statement. Some dairy cows are processed into ground beef when they grow old.
On Monday, the USDA began requiring lactating dairy cows to test negative for bird flu before being moved across state lines as officials sought to contain the virus.
The department said this weekend that testing is not required for cows that are shipped over state lines directly to slaughter facilities from barns where they are sold. Those cattle only need documentation showing they were inspected by a veterinarian.
The USDA said it inspects each animal before slaughter, and all cattle carcasses must pass inspection after slaughter to enter the human food supply.
Last week, USDA said it had found bird flu in a lung tissue sample from an asymptomatic dairy cow that was sent to slaughter from an infected herd. According to the department, the animal did not enter the food supply.
According to the statement, the USDA is now collecting beef muscle samples at slaughter facilities of condemned dairy cattle to determine the presence of viral particles. The USDA said that any positive PCR tests for retail or slaughter samples will be evaluated for live virus.
According to the statement, the USDA will also use a “virus surrogate” in ground beef and cook it at different temperatures to determine how the virus is affected. It said cooking meat to a safe internal temperature kills bacteria and viruses
According to the USDA, Colombia restricted the import of beef and beef products from U.S. states where dairy cows tested positive for avian influenza as of April 15. There are no known cases of bird flu in beef cattle so far.
