The Food and Drug Administration said Tuesday that fragments of the bird flu virus had been detected in some samples of pasteurized milk in the U.S. While the agency maintains that the milk is safe to drink, it notes that it is still waiting on the results of studies to confirm this.

The findings come less than a month after an outbreak of the H5N1 strain of bird flu was found, for the first time, in herds of dairy cows in several states. It has since been detected in herds in eight states. ⠀

The FDA is specifically testing whether pasteurization inactivates bird flu in cow milk. The findings will be available in the “next few days to weeks,” it said. ⠀

Still, the virus remains a cause of concern among health officials, given its particularly high mortality rate of around 50%. Bird flu doesn’t spread easily from person to person, but there’s worry that it could mutate as it spreads among cows to a version that spreads more easily among people. So far, there’s no evidence indicating that has happened, according to the CDC.

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