The U.S. Food and Drug Administration said Tuesday that samples of pasteurized milk had tested positive for remnants of the bird flu virus that has infected dairy cows.
The agency stressed that the material is inactivated and that the findings “do not represent actual virus that may be a risk to consumers.” Officials added that they’re continuing to study the issue.
“To date, we have seen nothing that would change our assessment that the commercial milk supply is safe,” the FDA said in a statement.
The announcement comes nearly a month after an avian influenza virus that has sickened millions of wild and commercial birds in recent years was detected in dairy cows in at least eight states. The Agriculture Department says 33 herds have been affected to date.
FILE – A line of Holstein dairy cows feed through a fence at a dairy farm in Idaho on March 11, 2009. As of April 11, 2024, a strain of the highly pathogenic avian influenza, or HPAI, that has killed millions of wild birds in recent years has been found in at least 24 dairy cow herds in eight U.S. states: Texas, Kansas, New Mexico, Ohio, Idaho, Michigan and North Carolina and South Dakota. (AP Photo/Charlie Litchfield, File)
FILE – Cases of eggs from Cal-Maine Foods, Inc., await to be handed out by the Mississippi Department of Agriculture and Commerce employees at the Mississippi State Fairgrounds in Jackson, Miss., on Aug. 7, 2020. The largest producer of fresh eggs in the United States said Tuesday, April 2, 2024 that it has stopped production at a Texas plant after bird flu was found in chickens there. Cal-Maine Foods, Inc. said in a statement that approximately 1.6 million laying hens and 337,000 pullets, about 3.6% of its total flock, were destroyed after the infection, avian influenza, was found at the facility in Parmer County, Texas. (AP Photo/Rogelio V. Solis, file)
FILE – Dairy cattle feed at a farm on March 31, 2017, near Vado, N.M. The U.S. Department of Agriculture said Monday, March 25, 2024, that milk from dairy cows in Texas and Kansas has tested positive for bird flu. (AP Photo/Rodrigo Abd, File)
FILE – Eggs are cleaned and disinfected at the Sunrise Farms processing plant in Petaluma, Calif., on Thursday, Jan. 11, 2024, which had seen an outbreak of avian flu. Egg prices are at near-historic highs in many parts of the world as the spring holidays approach, reflecting a market scrambled by disease, high demand and growing costs for farmers. (AP Photo/Terry Chea)
FILE – A baby harbor seal rest of Eastern Egg Rock off the coast of Maine in this July 9, 2007 file photo. Seal die-offs from the bird flu have been detected everywhere from New England to Chile. (AP Photo/Robert F. Bukaty, file)
FILE – A young harbor seals rests on a small island in Casco Bay, off Portland, Maine, in this Sept. 16, 2020 file photo. Avian influenza is killing tens of thousands of seals and sea lions in different corners of the world, disrupting ecosystems and challenging scientists who don’t see a clear way to slow the devastating virus. (AP Photo/Robert F. Bukaty, files)
Mike Weber watches an employee clean a hen house at his egg farm in Petaluma, Calif. on Thursday, Jan. 11, 2024. His company Sunrise Farms had to euthanize 550,000 chickens after avian flu was detected among the flock. A year after the bird flu led to record egg prices and widespread shortages, the disease known as highly pathogenic avian influenza is wreaking havoc in California, which escaped the earlier wave of outbreaks that that devastated poultry farms in the Midwest. (AP Photo/Terry Chea)
A worker moves crates of eggs at the Sunrise Farms processing plant in Petaluma, Calif. on Thursday, Jan. 11, 2024, which has seen an outbreak of avian flu in recent weeks. (AP Photo/Terry Chea)
File – A hen stands next to an egg, Jan. 10, 2023, at a farm in Glenview, Ill. Nearly 5 million chicken, turkeys and ducks have been slaughtered this year because of a persistent bird flu outbreak that began in 2022, but as big as that number may sound, it’s far less than the number of birds killed last year and that means consumers generally aren’t seeing as much impact on poultry and egg prices. (AP Photo/Erin Hooley, File)
FILE- Turkeys stand in a barn on a farm near Manson, Iowa, Aug. 10, 2015. Nearly 5 million chicken, turkeys and ducks have been slaughtered this year because of a persistent bird flu outbreak that began in 2022, but as big as that number may sound, it’s far less than the number of birds killed last year and that means consumers generally aren’t seeing as much impact on poultry and egg prices. (AP Photo/Charlie Neibergall, File)
FILE – Chickens walk in a fenced pasture at an organic farm in Iowa on Oct. 21, 2015. Another 1.2 million chickens will have to be slaughtered after bird flu was confirmed on an Iowa egg farm in the second massive case this week just days after nearly 1 million chickens had to be killed on a Minnesota egg farm. (AP Photo/Charlie Neibergall, File)
FDA officials didn’t indicate how many samples they tested or where they were obtained. The agency has been evaluating milk during processing and from grocery stores, officials said. Results of additional tests are expected in “the next few days to weeks.”
The PCR lab test the FDA used would have detected viral genetic material even after live virus was killed by pasteurization, or heat treatment, said Lee-Ann Jaykus, an emeritus food microbiologist and virologist at North Carolina State University
“There is no evidence to date that this is infectious virus and the FDA is following up on that,” Jaykus said.
Officials with the FDA and the USDA had previously said milk from affected cattle did not enter the commercial supply. Milk from sick animals is supposed to be diverted and destroyed. Federal regulations require milk that enters interstate commerce to be pasteurized.
Because the detection of the bird flu virus known as Type A H5N1 in dairy cattle is new and the situation is evolving, no studies on the effects of pasteurization on the virus have been completed, FDA officials said. But past research shows that pasteurization is “very likely” to inactivate heat-sensitive viruses like H5N1, the agency added.
Matt Herrick, a spokesman for the International Dairy Foods Association, said that time and temperature regulations for pasteurization ensure that the commercial U.S. milk supply is safe. Remnants of the virus “have zero impact on human health,” he wrote in an email.
Scientists confirmed the H5N1 virus in dairy cows in March after weeks of reports that cows in Texas were suffering from a mysterious malady. The cows were lethargic and saw a dramatic reduction in milk production. Although the H5N1 virus is lethal to commercial poultry, most infected cattle seem to recover within two weeks, experts said.
To date, two people in U.S. have been infected with bird flu. A Texas dairy worker who was in close contact with an infected cow recently developed a mild eye infection and has recovered. In 2022, a prison inmate in a work program caught it while killing infected birds at a Colorado poultry farm. His only symptom was fatigue, and he recovered.
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