The United States Will Conduct a Survey on Dairy Cows Sent to Slaughter to Study Cases of Avian Influenza

Regulators will examine the cows to understand how widespread the virus is and to determine if aging and cooking disrupt its activity.

The United States will track cases of avian influenza in dairy cows brought to slaughterhouses to understand how the virus might affect meat. They will also continue testing raw milk cheeses to see if the virus is deactivated during the aging process.

This renewed focus on the food chain in the U.S. is the latest effort to combat the highly contagious avian influenza virus, H5N1, which has raised alarms worldwide as a potential future pandemic.

Regulators will examine 800 samples from dairy cows at slaughterhouses. Dairy cows are typically slaughtered when they no longer produce milk or are retired, and they account for about 10% of beef production in the U.S., usually as ground beef.

The new cattle survey, starting in mid-September, will give us a better understanding of how common the virus is in dairy beef across the country. This nationwide study should provide clearer insights. insights into potential risks.

If a sample tests positive, the U.S. Department of Agriculture will purchase the carcass for further testing. Such studies might include determining if the virus is viable—whether it can reproduce in a lab—and identifying the temperature at which it is killed.

A previous survey in May tested 109 samples of muscle tissue from cows showing signs of illness after slaughter, and researchers found H5N1 particles in one dairy cow. That animal was removed from the food supply. Another survey sampled ground beef available in stores, and none of the meat tested positive.

In another study, scientists injected ground beef with a mock virus and then cooked it. José Emilio Esteban, Under Secretary for Food Safety at the USDA, said the 300-gram hamburger patty was thicker than what consumers might find in fast-food restaurants, making it “thick enough to represent the worst-case scenario.”

However, cooking it thoroughly deactivated the virus, he said.

At a medium temperature (145°F/63°C) and a well-done temperature (160°F/71°C), the virus was not detected.** The U.S. Department of Agriculture’s Food Safety and Inspection Service has long recommended these internal temperature levels.

Esteban said, “If you cook it under these conditions, it should be very safe to eat.”

According to the USDA report, at a temperature of 120°F/49°C, or rare, the “mimic virus was significantly deactivated” in burgers even with high levels of the virus added.

Callie Kneel, a professor of microbial food safety at the University of Delaware, said fully cooking meat helps eliminate all types of foodborne pathogens. She added, “Consumers should be aware of the potential for disease transmission and the control they have in their own kitchens.”

But only about a quarter of Americans check the internal temperature of meat with a food thermometer, a rate that “isn’t as high as anyone would like.”

She said that ground beef is usually made from multiple cows, increasing the risk of foodborne illnesses when not fully cooked.

Kneel said, “We know that burgers are always riskier for these pathogens.” But “all virus particles will be deactivated [with full cooking] if there are any. So you won’t just kill Salmonella, but you also won’t be at risk for avian flu.”

The new study will focus on meat from dairy cows only.

In experiments, scientists were able to infect calves through their noses, but they believe the outbreak appears to primarily spread among lactating dairy cows through shared milking equipment and human intervention, according to the USDA.

It is unclear if any beef cattle have been tested for the H5N1 virus.

Kneel said, “If you start testing and looking for things, you might find them.” But in terms of food safety risks, she said, “I think we can control it through some behavioral changes and existing monitoring practices.”

The U.S. Food and Drug Administration (FDA) also announced on Tuesday that ongoing tests showed that pasteurization completely inactivates the avian flu virus in milk, making pasteurized milk supplies safe to drink.

They examined 167 dairy products, including butter and cheese made from raw milk, available in stores in 27 states in June and July. Officials said about 17% of the products contained inactive viral particles, but none were viable.

Agency officials said that hard cheese made from raw milk and then stored for at least 60 days showed no trace of the virus—so they could not yet determine whether the aging process inactivates the virus.

For the cheese made from raw milk that we tested, none of the samples showed any viral genetic material. This suggests that the herd producing the milk is likely free of the virus. milk used to make the cheese was not infected at the time of milking,” said Steve Grob, chief medical officer at the FDA’s Center for Food Safety and Applied Nutrition.So, we can’t really say for sure if making and aging cheese from unpasteurized milk is enough to kill the virus.

There has been increased interest in drinking raw milk, which can carry deadly pathogens and has no benefits compared to pasteurized milk, during this outbreak.

Officials continue to warn that drinking raw milk is dangerous. Grob said, “Consuming raw milk poses a risk to consumers.”

This has been true long before the avian flu outbreak.

Kneel said, “This is the one thing I always tell people: If there’s anything to avoid because of foodborne illnesses, it’s definitely raw milk.” Even seemingly healthy cows can carry pathogens that are deadly to humans. Here’s a more human-friendly version:

“There’s a risk of getting sick from drinking raw milk, especially from bacteria like E. coli.” coli, Cryptosporidium, Listeria, Salmonella—it’s all really high.”

She said that a single Shiga toxin-producing E. coli bacterium could kill a person, and a hundred Salmonella cells could make someone sick for the rest of their life.

It is not yet clear if consuming raw milk could cause infection with the H5N1 virus, but it appears to affect some mammals this way. Mice fed with H5N1-infected milk became sick quickly, and several cats in barns that were fed infected cow’s milk died.

Kneel said, “We don’t know what consuming H5N1 virus in milk might do to people.”