Bird flu particles were found in pasteurized milk. A former surgeon general says he isn't changing what he eats.

• H5N1 avian influenza, also called bird flu, is spreading through US chickens and now cattle.
• The FDA discovered genetic material from the virus in grocery store milk.
• Former surgeon general Dr. Jerome Adams explains why he's still eating milk, eggs, and meat.

Milk might contain remnants of the H5N1 bird flu virus that's raging through US chickens and cattle.

The Food and Drug Administration announced Tuesday that it had discovered virus particles in "some of the samples collected" throughout the milk supply chain, from the cow to the shelf. The agency did not indicate how many samples tested positive or from where, but said the detections "do not represent actual virus that may be a risk to consumers."

However, the discovery suggests the virus has spread further through the US cattle population than officials previously realized. Scientists are growing more concerned that this avian influenza outbreak could make the jump into human-to-human transmission.

So far, though, many public health experts don't think this rings alarm bells about the safety of the food supply.

"I had eggs yesterday and I had milk last night, and I'll have a steak if someone gives me a steak," Dr. Jerome Adams, who was the surgeon general of the Trump administration and is now the director of health equity at Purdue University, told Business Insider on Wednesday.

"I still believe that the way we process and cook foods is going to disable most bacteria and viruses, including this one," he said.

Pasteurization should kill H5N1 in milk

The FDA oversees the nation's milk supply, and the US Department of Agriculture oversees dairy cows. Both say they believe the commercial milk supply is safe, due to the pasteurization process and the practice of disposing of milk from sick cows.

Pasteurization heats milk at a high temperature for a brief period of time to kill microbes living inside it. Some states allow the sale of unpasteurized, aka "raw," milk or cheese, which the CDC recommends avoiding.

Public-health experts told The Washington Post and The New York Times on Tuesday that they, too, believe pasteurized milk to be safe, but that the federal government should still conduct tests to confirm that. The FDA says such tests are ongoing.

"It's taking them too long to be able to reassure the public about the safety of milk," Adams said.

Some studies have shown that pasteurization deactivates H5N1 in eggs, the FDA says, and that happens at a lower temperature than milk pasteurization.

"To date, we have seen nothing that would change our assessment that the commercial milk supply is safe. Results from multiple studies will be made available in the next few days to weeks," the FDA statement said.

To be extra safe, cook meat and eggs all the way

There's probably no "significantly increased risk," Dr. Samuel Alcaine, an associate professor of food science at Cornell University, told Business Insider on April 6, but you can be extra safe by fully cooking your meat and eggs (until the yolk is firm).

Adams says he doesn't normally eat rare steak or runny eggs anyway.

"That has nothing to do with H5N1. That's just me being someone who's been in public health and food safety for a long time," he said.

His wife does eat runny eggs and rare steak, though, he added, "and I'm not telling her to change what she does."

He added that people should still follow basic food-safety practices: Wash your hands after handling raw meat or eggs, and before handling the food you'll eat. Prevent cross-contamination from raw meats or eggs and the utensils that have touched them. Always cook poultry to an internal temperature of at least 165 degrees Fahrenheit.

The biggest bird flu risk for humans isn't food

The people who are really at risk for bird flu are those who work closely with chickens, cattle, or other livestock.

The CDC says those workers should avoid unprotected, direct contact with sick animals, raw milk, animals' drinking water, animal carcasses, feces, litter, or other surfaces that could be contaminated with animals' saliva, blood, or other excretions. Workers should be provided with personal protective equipment for those situations and trained to use it properly, the agency says.

"It's spreading rapidly in these animals, and every time it spreads, it has a chance to mutate," Adams said.