April 29, 2024 – The FDA confirmed that the virus that causes bird flu is effectively inactivated by the technique of heating milk, called pasteurization.
Recently, concerns arose when dairy cows and a farm employee tested positive for the H5N1 bird flu. Officials said the human infection was likely because of close contact with infected cows. The situation prompted FDA officials to check samples of commercially available milk.
These latest results come from further laboratory tests of pasteurized milk that originally suggested the samples contained inactive fragments of the bird flu virus. Scientists had widely expected these later results.
“These additional tests did not detect live, infectious viruses. These results confirm our assessment that the commercial milk supply is safe,” the FDA said in a Press release late Friday, adding that the outcomes were “preliminary.”
Tests of several samples of powdered infant formula and powdered milk products marketed as toddler formula were completely negative, “indicating that no virus fragments or viruses were detected in the milk formula products,” the FDA press release continued.
It is unclear how widespread the virus is amongst cattle within the United States. The U.S. Department of Agriculture currently lists 33 positive test leads to dairy cows dating back to March 25 and picked up from Texas livestock. The cows in these 33 positive test results lived in six other states besides Texas: Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio and South Dakota.
One in five samples of pasteurized milk tested by the FDA was found to contain fragments of genetic material consisting of inactive parts of the bird flu virus, the agency reported. The FDA says additional testing is currently underway on 297 samples of dairy products from 38 states.
In recent years, bird flu has been detected in an increasing variety of animals. The virus is already widespread amongst wild birds and sporadically infects chicken flocks in business and hobby farming. Infections in humans have also been reported occasionally worldwide, normally because of close contact with infected birds.
Like other viruses, H5N1 evolves over time. Federal agencies recently released data on U.S. infections which can be available to the scientific community. Evolutionary biologist on the University of Arizona Michael Worobey, PhD, announced on Sunday on X (formerly Twitter) that he and his colleagues had published the newly genetic data of 202 cows, nine cats, 18 chickens, a skunk, a raccoon, three grackle birds, two blackbirds, a Canada goose, a peregrine falcon and a goose.
The news agency Reuters reported Worobey said genetic differences between the infected cattle employees and the animal samples suggested that “this was a very long-lasting, widespread epidemic.”