CBS News – A “small but detectable quantity” of infectious H5N1 bird flu virus was able to survive a common approach to pasteurizing milk, according to new research co-authored by scientists at the National Institutes of Health.
The findings, published Friday in The New England Journal of Medicine, were based on experiments run at the agency’s lab. The researchers note this is not the same as finding infectious H5N1 virus in milk from grocery stores.
So far, officials have not detected infectious virus in any supermarket milk samples.
The finding comes as authorities are still identifying new infected herds in this year’s unprecedented outbreak of H5N1 bird flu in dairy cattle.
Infections have been detected in cows across farms in at least a dozen states, with most of the positive tests coming from raw milk samples that were teeming with the virus.
Authorities have called on states to curb raw milk sales that could spread the virus, and have warned consumers against drinking raw milk.
“The study reflected experimental conditions, and should not be used to draw any conclusions about the safety of the U.S. milk supply,” a Food and Drug Administration spokesperson said in a statement.
In the real world of commercial dairy processing, milk from infectious cows is likely being mixed with milk from healthy cows, diluting the virus and making it less likely there would be enough of it to survive.
Technical details of how the milk is pasteurized, as well as additional steps to treat the milk, also cut the risk. Pasteurization involves treating the milk at high temperatures for a period of time to kill contamination.
Results from previous FDA studies of 297 samples of retail dairy products like milk and yogurt did not turn up any infectious virus. Earlier tests found only some harmless fragments of the virus leftover from pasteurization …
