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Federal officials say the risk to the public remains low after the Food and Drug Administration announced Wednesday that tests of commercial milk found traces of avian influenza.
The announcement comes amid a nationwide outbreak of highly pathogenic avian influenza (HPAI) among dairy cows, which was first confirmed late last month. The disease, which is highly contagious and often fatal in birds, has spread to the following areas: a cluster of at least eight states. At least one person who probably came into contact with the sick animal also contracted the virus.
But government officials and scientific experts say so far there is no evidence that pasteurized milk contains infectious viruses.
Jeanne Marazzo, director of the National Institute of Allergy and Infectious Diseases, said in a call with reporters Wednesday that tests conducted on retail milk showed the presence of genetic material from the virus.
Marrazzo said attempts to grow the virus from these samples showed it was not infectious or “alive,” adding that testing was only done on a small number of samples.
“To date, we have not seen anything that would change our assessment that the commercial milk supply is safe,” the FDA said in a statement.
If pasteurization inactivates viruses, why do they appear in milk?
Pasteurization is carried out used in the US It takes decades to kill harmful bacteria and viruses in milk, but pasteurization does not erase all traces of viruses.
Some genetic material may remain after the pasteurization process. Samuel Arcane, a professor of food science at Cornell University, said DNA, or RNA, is the “instructions” that tell the virus what to do.
“Cars get into accidents. The car doesn’t work anymore. You can’t drive it. You can’t do anything the car does. But if you dig through the rubble, you’ll find that the owner’s manual that tells you how to drive the car is still there. You might find it. “Go to work,” he said.
Alkain said this is likely what is happening with avian influenza in milk. Tests have shown that the virus was present before, but is now unable to cause infection.
The FDA said no specific studies have been conducted on whether pasteurization inactivates avian influenza in milk because the infection in cows is so new. However, previous research has shown that pasteurization is “very likely to effectively inactivate heat-sensitive viruses such as H5N1,” and that pasteurization can reduce avian influenza in eggs. It is inactivated and this process takes place at a lower temperature than milk, it added.
The FDA detected avian influenza in milk using a quantitative polymerase chain reaction (qPCR) test, but said this “does not represent the actual virus that may pose a risk to consumers.” .
The FDA said further evaluation of the milk samples will be done using an egg inoculation test, which it calls the “gold standard for determining viable virus.” The agency said it would publish the results of several studies in the coming days or weeks.
Is it still safe to drink milk?
Alkain said there were “no safety concerns” about the milk containing traces of bird flu. “I still buy milk from my local grocery store.”
Federal officials stress that milk from infected cows should be discarded or destroyed and does not enter the human food supply.
Additionally, milk sold through interstate commerce in the United States must be pasteurized. The FDA encourages consumers not to drink unpasteurized raw milk.
But Alcain said the flu is not generally transmitted through food, and the more pressing concern is protecting people, such as farm workers, who may come into close contact with infected animals. .
In an effort to further contain the outbreak, the Department of Agriculture’s Animal and Plant Health Inspection Service announced: order Steps taken Wednesday include requiring dairy cows to test negative for bird flu before traveling across state lines.