Agriculture Department to Require Testing of U.S. Milk Supply for Bird Flu Virus

The new rules call for testing unpasteurized milk from dairies across the country and for farm owners to provide details that would help officials identify and track cases more easily.

The U.S. Department of Agriculture announced new rules on Friday requiring the testing of the nation’s milk supply for the bird flu virus known as H5N1, nearly a year after the virus began circulating through dairy cattle.

Under the new testing strategy, the department will begin testing bulk samples of unpasteurized milk from dairy processing facilities across the country.

Farmers and dairy processors will be required to provide samples of raw milk on request from the government. The rules also require farm owners with infected herds to provide details that would help officials identify more cases and contacts.

The rules are a departure from the voluntary guidance that the department has issued during the outbreak. Many dairy farms have not complied with voluntary testing of milk or of dairy workers, leaving federal officials in the dark about how widely the virus might have spread.

Many experts in the United States and elsewhere, including with the World Health Organization, have sharply criticized the lack of testing of cattle and of people who may be infected with the virus. The virus does not yet spread easily among people, but every untreated infection is an opportunity for it to gain the ability to do so, experts have said.

No one has been known to become ill from drinking raw milk, although farm animals, including cats, are thought to have died after consuming contaminated milk. Pasteurized milk sold to consumers has already been shown to be free of the virus.