The US Food and Drug Administration announced Tuesday that samples of pasteurized milk tested positive for remnants of the avian flu virus, which has affected dairy cows.
The FDA emphasized that the material has been inactivated and that the findings “do not represent actual virus that may pose a risk to consumers.” Officials stated that they are still investigating the situation.
“To date, we have seen nothing that would change our assessment that the commercial milk supply is safe,” the FDA stated in a statement.
The news comes about a month after an avian influenza virus, which has infected millions of wild and commercial birds in recent years, was found in dairy cows in eight states. The Agriculture Department reports that 33 herds have been affected to yet.
FDA authorities did not say how many samples they tested or where they were obtained. According to officials, the FDA has been assessing milk both during processing and at grocery stores. Additional test results are expected during “the next few days to weeks.”
The FDA’s PCR lab test would have detected viral genetic material even after the live virus had been killed by pasteurization, or heat treatment, according to Lee-Ann Jaykus, an emeritus food microbiologist and virologist at North Carolina State University.
“There is no evidence to date that this is an infectious virus and the FDA is following up on that,” Jaykus said in a statement.
Officials with the FDA and USDA previously stated that milk from infected cattle did not enter the commercial supply. Milk from unwell animals should be diverted and destroyed. According to federal requirements, milk entering interstate commerce must be pasteurized.
Because the finding of the avian flu virus known as Type A H5N1 in dairy cattle is new and the situation is changing, FDA authorities stated that no studies on the effects of pasteurization on the virus have been performed. However, previous research indicates that pasteurization is “very likely” to inactivate heat-sensitive viruses such as H5N1, the agency warned.
According to Matt Herrick, spokesman for the International Dairy Foods Association, pasteurization time and temperature requirements maintain the safety of the commercial milk supply in the United States. Virus remnants “have zero impact on human health,” he added in an email.
Scientists identified the H5N1 virus in dairy cows in March, following weeks of complaints that cows in Texas were suffering from an unknown illness. The cows were lethargic, and milk output dropped dramatically. Although the H5N1 virus is fatal to commercial poultry, most sick cattle appear to recover within two weeks, specialists say.
To date, two persons in the United States have been infected with bird flu. A Texas dairy worker who had close touch with an infectious cow recently suffered a small eye infection and has since recovered. In 2022, a prison inmate participating in a work program contracted the virus while killing diseased birds on a Colorado poultry farm. His sole symptom was weariness, and he recovered.