Beef tissue from a sick dairy cow has tested positive for the bird flu virus, federal officials said on Friday.
The department continued to stress that the commercial food supply remained safe.
But the positive test, which came as part of an ongoing federal study of beef safety, raises concerns about whether the virus might make its way into the commercial beef supply, posing a health risk to humans.
Just one cow tested positive, the department said.
Meat from condemned cows is not allowed in the commercial food supply.
Organizations:
U.S . Department of Agriculture, Service