Bird flu typically spreads among birds, but there have been recent outbreaks among cattle in the U.S., and one Texas man contracted the virus from sick cows. Here’s why so many experts are worried about a possible new pandemic.

The U.S. Food and Drug Administration said on Wednesday that preliminary results of additional testing of more dairy products has shown that pasteurization inactivates the bird flu virus. The FDA released results from tests of products including sour cream and cottage cheese,