US tests show pasteurized milk is safe as bird flu spreads to Colorado

By Julie Steenhuysen, Tom Polansek

(Reuters) -Additional tests of milk showed that pasteurization killed the bird flu virus, federal health officials said on Friday, as Colorado became the ninth U.S. state to report an infected dairy herd.

Federal lawmakers urged the Biden administration to further contain the spread of the virus as tests showed one in five commercial milk samples in the US contained remnants of the virus, indicating the outbreak is more widespread than previously thought.

The U.S. Food and Drug Administration (FDA) said late Friday that preliminary results from gold standard PCR testing showed pasteurization killed the virus in milk and baby food. The company did not say how many milk products it had tested, but added that it plans to conduct more tests on 297 products from 38 states.

One person, a Texas farm worker, has been confirmed to have had bird flu and contracted conjunctivitis after exposure to dairy cows during the current outbreak. Both the Centers for Disease Control and Prevention and the World Health Organization said Friday that the current overall public health risk is low but higher for people exposed to infected animals.

The U.S. Department of Agriculture has confirmed that dairy cows in Colorado tested positive, following previous infections in Texas, Kansas, Michigan, Ohio, Idaho, New Mexico, North Carolina and South Dakota.

Members of Congress’ push for a stronger response increased pressure on federal agriculture and health authorities, who are still trying to confirm how the H5N1 virus spreads and its potential risks to humans, a month after its first detection in a dairy herd in Texas.

An analysis of U.S. Department of Agriculture data by a University of Arizona scientist offers new evidence that the first known H5N1 outbreak in dairy cattle is more far-reaching than the 34 herds in nine states that have officially tested positive.

“It is crucial to contain this before it spreads among people. Given the lessons learned from COVID, this federal response is insufficient,” Republican U.S. Senator Mitt Romney said in a post on X.

Some lawmakers, including Romney, have launched a bipartisan effort to reauthorize the legislation, known as the Pandemic and All Hazards Preparedness Act. This law expired last year and is intended to strengthen the country’s response to pandemics and other public health threats. The recent spread of bird flu and the detection of genetic material from the H5N1 virus in milk have increased calls for action.

In the case of humans, the virus differs significantly from the bird flu virus samples taken from infected livestock and made public by government officials last weekend, said Dr. Michael Worobey, an evolutionary biologist from the University of Arizona.

The difference between the genetic sequences of the worker virus and the 239 other samples provided indicates that “this was a very long-lasting, widespread epidemic,” he told Reuters.

The Texas Animal Health Commission said it did not receive the location of the employee’s farm or obtain samples from that herd for testing due to the person’s confidentiality.

“I think the sequences that are out there are probably not representative of everything that’s circulating,” said Dr. Richard Webby, a virologist at St. Jude’s Children’s Research Hospital in Memphis.

A CDC spokesperson said in an email, “There are always some subtle changes in genetic sequences as influenza viruses move from host to host,” but the data indicates that the virus emerges from birds to infect cows and then is transmitted to humans.

BIRD FLU TRACES FOUND IN AMERICAN MILK

One in five commercial milk samples tested in a nationwide survey contained particles of the H5N1 virus, the FDA said late Thursday. The agency said there is no reason to believe the virus found in milk poses a risk to human health and described the results of the new tests on Friday.

“What this says is that this virus has largely saturated dairy cattle across the country,” said Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota.

Many infectious disease experts and government officials have said they believe the pasteurization process will inactivate the virus, also known as bird flu.

“I don’t worry about the milk itself,” says Samuel Alcaine, an associate professor of nutritional sciences at Cornell University. “It does indicate that the virus is more widely spread among dairy companies than we previously thought.”

Osterholm said the U.S. should do much more sampling, in dairy and beef cattle as well as in pigs.

Democratic U.S. Sen. Tammy Baldwin of Wisconsin, a large dairy state with no reported cases, urged the USDA to “quickly deploy additional resources to states that have the ability to prevent the disease from entering herds.”

The White House has said it is monitoring the bird flu situation and is launching an “immediate response team” to ensure the safety of the nation’s food supply, monitor trends to limit risks and prevent the spread or prevent virus.

Starting Monday, the USDA will require dairy cows to test negative for bird flu before moving them across state lines.

In Indiana, officials are weighing their own possible restrictions, such as testing within the state, even though there have been no confirmed cases, said Bret Marsh, the state veterinarian.

“We’re looking here at the state level to see what we might need to do,” he said on a conference call.

(Reporting by Julie Steenhuysen and Tom Polansek in Chicago; Susan Heavey, Richard Cowan and Trevor Hunnicutt in Washington; and Leroy Leo and Bhanvi Satija in Bengaluru; Editing by Tasim Zahid and Josie Kao)