The U.S. government said Monday it is collecting samples of ground meat for testing at retail stores in states where avian influenza is occurring in dairy cows, but remains confident the meat supply is safe.
Federal authorities are calling for verification of the safety of milk and meat after confirming H5N1 virus infections in 34 dairy herds in nine states and one herd in Texas since late March.
Both the U.S. Centers for Disease Control and Prevention and the World Health Organization say the overall public health risk is low, but the risk is high for people who come into contact with infected animals.
Scientists believe the outbreak in cattle is more widespread than officially reported, based on findings that H5N1 particles were detected in about 20% of milk samples.
However, the U.S. Food and Drug Administration announced Friday that preliminary results from a gold standard PCR test show that pasteurization kills the avian influenza virus in milk.
The U.S. Department of Agriculture will analyze retail ground meat samples with a PCR test to show “the presence of viral particles,” and will conduct two additional safety investigations, the statement said. Some dairy cows are processed into ground meat as they grow older.
“Additional USDA inspections are appropriate to ensure public health is protected and to stop the spread of animal disease,” said Sarah Little, a spokeswoman for the Meat Institute, an industry group representing meat processors. .
As officials seek to contain the virus, the Department of Agriculture on Monday began requiring lactating dairy cows to test negative for avian influenza before being moved across state lines.
The department announced this weekend that testing will not be required for cattle that are transported directly from selling barns across state lines to slaughter facilities. These cows only require documentation that they have been examined by a veterinarian.
The USDA said it inspects each cow before slaughter and all cow carcasses must pass inspection after slaughter in order to be included in the human food supply.
The USDA is also currently collecting cow muscle samples at the condemned dairy cow slaughter facility to confirm the presence of virus particles, the statement said. The USDA said any positive PCR tests on retail or slaughterhouse samples will be evaluated for live virus.
The Department of Agriculture announced last week that avian influenza was found in lung tissue samples from asymptomatic dairy cows sent for slaughter from infected herds. The animal was not in the food supply, the department said.
In a separate safety study, the USDA will cook ground meat containing a “viral surrogate” at various temperatures to assess how the virus is inactivated, the statement said. Cooking meat to a safe internal temperature kills bacteria and viruses.
As of April 15, Colombia restricted the import of beef and beef products from U.S. states where dairy cows have tested positive for avian influenza, according to the Department of Agriculture.
To date, there are no known reports of avian influenza in beef cattle.
The human case in this outbreak was a Texas farm worker who developed conjunctivitis from contact with dairy cows.
