Bird Flu Found in Beef Tissue; Officials Say It Did Not Enter Food Supply

TUESDAY, May 28 -- Bird flu virus has been detected in beef tissue from a sick dairy cow, but U.S. health officials stressed the country's meat supply remains safe.

In an update issued Friday, the U.S. Department of Agriculture (USDA) said the cow had been culled because it was sick and the meat did not enter the food supply.

The agency stressed that it "is confident that the meat supply is safe. USDA has a rigorous meat inspection process, which includes Food Safety and Inspection Service [FSIS] veterinarians who are present at all federal livestock slaughter facilities. FSIS personnel inspect each animal before slaughter, and all cattle carcasses must pass a second inspection after slaughter and be determined to be fit to enter the human food supply."

So far, the agency "has conducted tests on beef tissue from 96 cull[ed] dairy cows condemned at select FSIS-inspected facilities... On May 22, 2024, viral particles were detected in tissue samples, including muscle, from one cow. To date, samples from 95 cows have tested negative for viral particles. No meat from these dairy cattle entered the food supply."

Still, the positive test raises concerns about whether the virus might eventually find its way into the commercial beef supply.

So far, the virus, also known as H5N1, has only been detected in dairy cattle and not in the beef cattle that are raised for meat. But experts believe the outbreak is bigger than what has been reported to this point.

“It’s evident that this is widespread and will require constant vigilance,” Brian Ronholm, director of food policy at Consumer Reports, told the New York Times.

While the overall risk to consumers remained low, he added “it will be important for consumers to make sure they cook meat to the proper temperature for additional assurance.”

Dr. Gail Hansen, an independent food safety and veterinary health expert, told the Times that, “People do eat meat rare and even raw. So, once again, the assurances from government agencies, before the science is in to confirm or deny the assumptions, continue to undermine the confidence by the public.”

The USDA said the fact that inspectors identified the ill cow and prevented its meat from entering the food supply proved that its safety protocols are working. The agency has not yet found virus in ground beef samples collected from retail outlets in states where cows have tested positive.

Earlier this month, the USDA released results from a study in which researchers added high concentrations of the virus to beef patties. The researchers found no virus when the meat was cooked to 160 degrees Fahrenheit (F), the internal temperature of a well-done burger, or 145 degrees F, the temperature of a medium-cooked burger.

But there was virus in rare burgers, cooked to 120 degrees, although at lowered levels.

“All indications are: You cook your food, even if there’s virus in there, it will kill it,” Stacey Schultz-Cherry, a virologist and influenza expert at St. Jude Children’s Research Hospital, told the Times.

Matthew Moore, a food science expert at the University of Massachusetts, told the Times that experts would like to know whether the virus found in the beef tissue was viable or inactivated. Whether people can contract bird flu by eating contaminated food also remains a mystery.

Still, a study published on Friday found that unpasteurized milk contaminated with the virus sickened mice, heightening concerns among experts that consuming raw milk could harm humans. A significant number of cats have also died after drinking contaminated raw milk, recent research showed.

More information

The CDC has the latest on bird flu.

SOURCES: U.S. Department of Agriculture, news release, May 24, 2024; New York Times