Inactive pieces of the bird flu virus have found their way into part of the U.S. food and milk supply amid the latest outbreak of the disease in animals. This comes as the virus, also known as bird flu, continues to spread among a growing number of mammals, most pressingly, dairy cattle. While the reports may seem scary, experts say these fragments are not dangerous and harmful versions of the virus are unlikely to end up in anything people eat or drink.
Here’s what you need to know about bird flu and the safety tests done on dairy, meat and more.
What’s happening to the milk?
Tests conducted by the U.S. Food and Drug Administration (FDA) detected genetic material, or RNA, from bird flu in about 20% of commercially sold milk samples collected across the country. Separate Tests of a smaller number of milk cartons on supermarket shelves by researchers at Ohio State University (OSU) and St. Jude’s Children’s Research Hospital found fragments of bird flu RNA in about 39% of 150 samples tested.
“That definitely suggests to me that it’s more widespread than we thought, but in some ways that’s not entirely unexpected.” Dr.associate professor of epidemiology and veterinary medicine at OSU and co-author of the smaller milk study, told Yahoo Life.
But the good news is that, along with the FDA tests, the tests conducted by Bowman and his co-author, Ricardo Webby, a professor of infectious diseases at St. Jude’s, found no samples with whole or viable bird flu viruses. Small portions of the virus are not capable of causing infection. Instead, Webby compares milk testing to on-screen detectives running DNA tests at a crime scene: “They’re not necessarily looking for the virus itself, just the evidence that it was there at some point,” Webby, who leads the World Health Organization (WHO) initiative to study influenza in birds and animals, told Yahoo Life.
Samples of commercially sold milk that contained virus fragments have been tested to see if these virus pieces can also grow in eggs or petri dishes, and so far, none of them have been able to do so. “If there was the entire virus in a sample, it would replicate and we would find it, but we couldn’t find any,” Webby said. The FDA reached the same conclusion after running the same types of tests.
All of this is evidence that pasteurization – the process used to sterilize milk – inactivates bird flu because it “breaks down the viral package,” explains Webby. Pasteurization is designed to kill all types of viruses and bacteria and make milk safer. Not pasteurized or raw milk represents less than 1% of US supply and is banned in 23 states and the District of Columbia. The FDA advises against drinking it because it can cause food poisoning.
With regular supermarket milk, there’s very little cause for concern at this point, according to Webby and Bowman.
What about other dairy products?
O FDA also tested cottage cheese and sour cream for bird flu. Once again, the agency found non-infectious traces of the virus, but pasteurization also inactivated bird flu in these products.
Authorities also tested infant formula and powdered milk derived from cow’s milk. The results were even better: there were no traces of viruses in any of these products. FDA scientists concluded that no further testing was needed to prove the products were safe.
Do I need to worry about eating beef?
The US Department of Agriculture (USDA) declared the US meat supply “secure” on May 1, according to Reuters. USDA officials tested 30 ground beef samples collected in states where cattle herds tested positive for bird flu. All samples tested negative for the virus.
Although infections have not been reported among herds of cattle raised for meat, dairy cattle—among which avian influenza has been widespread—are sometimes used for ground beef. Webby says the flu is unlikely to reproduce in muscle, but it’s unclear whether it could occur in other parts of the animal that are processed into ground beef. Still, he says the highest concentrations of bird flu have consistently been found in milk, and that safe handling and use cooking meat – not allowing cross-contamination in the kitchen and cooking meat to an internal temperature of at least 145°F – should kill any viruses.
Are eggs a concern?
Bird flu has been found in laying hens, including those kept by Cal-Maine Foods, which is the largest manufacturer in the US. But the CDC says it’s unlikely anyone would get bird flu from eating eggs.
For one, you shouldn’t eat raw eggs, which can make you sick from other pathogens like listeria. Just like beef, cooking eggs to a proper temperature of 135°F to 165°F (depending on how you are preparing them) should kill any bacteria or viruses, including bird flu.
Webby adds that bird flu is extremely fatal to chickens, so most of those infected will die, and farmers immediately cull all affected flocks, since only bird flu-free eggs and chickens can be sold in the U.S. and the birds are tested regularly by regulators.
