University of Georgia researchers are partnering with the U.S. Food and Drug Administration to better understand the risk of the bird flu virus in milk and steps needed to ensure milk safety.
The research comes at a time of an expanding bird flu outbreak affecting the nation’s dairy cows which has scientists increasingly worried the virus could be transmitted to humans through raw milk.
It’s not yet known if a live avian flu virus can be transmitted to people who consume raw milk. At this point, it is largely theoretical. At least a half dozen cats have died after consuming raw milk containing the virus.
Milk produced for mass consumption undergoes pasteurization, a process by which milk is heated to a specific temperature for a set time to kill harmful bacteria that can lead to diseases.
In most milk processing plants, chilled raw milk is heated by passing it between heated stainless-steel plates until it reaches 161 degrees Fahrenheit, according to U.S. Dairy. It’s then held at that temperature for at least 15 seconds before it’s quickly cooled back to its original temperature of 39 degrees.
The FDA and the U.S. Department of Agriculture have indicated the commercial milk supply is safe because of both the pasteurization process and that milk from sick cows is being diverted or destroyed.
Raw dairy products, however, are another story.
“The question that remains is there is a very large industry around raw or partially pasteurized dairy products whether it’s raw cheese or raw milk and (the FDA) is trying to understand how different pasteurization processes effects the virus,” said S. Mark Tompkins, director and principal investigator of the UGA Center for influenza Disease and Emergence Research.
UGA researchers are joining four institutions, Cornell University, University of Wisconsin-Madison, and St. Jude Children’s Research Hospital and the National Institutes of Health’s Rocky Mountain Labs in Montana, to support the FDA’s efforts to analyze the effectiveness of various temperature and time thresholds outside standard pasteurization practices to better determine at what point the bird flu virus is killed.
There have been no human cases of bird flu in Georgia. There have also been no cases in dairy herds in Georgia.
Bacteria commonly found in raw milk include listeria, campylobacter, salmonella and E. coli. Illnesses caused by these bacteria can be especially serious for young children, pregnant women, the elderly and the immunocompromised.
From 1998 to 2018, the Centers for Disease Control and Prevention documented more than 200 illness outbreaks traced to raw milk, which sickened more than 2,600 people and hospitalized more than 225.
So far, there are no confirmed cases of people getting bird flu from drinking raw milk. Tompkins said he believes there’s a serious potential health risk, and urges people to avoid consuming raw milk and raw milk products.
Credit: Andrew Davis Tucker
Credit: Andrew Davis Tucker
“We all wear seat belts. It’s the law now, but people wear seat belts because it reduces the risk of serious injury if you are in a car wreck,” he said. “The same could be said for consuming raw milk products. If you consume raw dairy products, you increase the risk of listeria or campylobacter or something else. Now we have H5N1 and if you consume a raw dairy product that’s contaminated with that, now you have the risk of infection.”
Tompkins said it’s possible someone gets mildly ill such as a case of pink eye. But it could be far more serious, he said.
“There is a risk this virus could cause more severe disease for yourself and then you would also be creating this great public health risk where it could be a means for this virus to change and now infect more people,” he said.
Raw milk has grown in popularity in recent years due to interest from consumers who believe raw milk tastes better and is more nutritious.
Last year, Georgia joined a growing number of states allowing dairy farmers to obtain a license to sell raw milk for human consumption, despite testimony from public health officials about the serious health risks it can pose.
A spokesperson for the state Department of Agriculture told The Atlanta Journal-Constitution Friday there is now one operation in Georgia licensed to sell raw milk for human consumption.
The state agency also allows dairy farms to sell raw milk as “pet milk” for animals, and it must be labeled that way.
Indications suggest Georgians are drinking raw “pet milk.”
A Facebook page dedicated to finding farmers who sell raw milk in Georgia has over 4,500 members, and one member in South Georgia said she was willing to drive up to three hours for it.
Meanwhile, the bird flu virus continues to expand since making the jump to cows earlier this year. Three dairy workers in California were infected with bird flu, according to the Centers for Disease Control. That brings the total of human cases up to 17 this year. The workers developed eye redness known as conjunctivitis and had mild symptoms.
California health officials said the workers were employed at different farms and there is no known link between the three cases, suggesting that they were infected through animal contact, not by people.
Bird flu can spread from animals to people in many ways, according to the CDC: if a person touches something contaminated with the virus and then touches their eyes, nose or mouth, or a liquid contaminated with live virus splashes into their eyes (like cow’s milk from an infected cow, for example).
The risk to the public remains low, they added.
Across the U.S., more than 290 dairy herds have been infected in 14 states since the outbreak of H5N1 bird flu was confirmed in March. Bird flu has been spreading in wild and domestic birds in the U.S. for several years, but only recently was found in dairy cows.
The Associated Press contributed to this article.
Human Cases by the Numbers
7: following exposure to infected dairy cows since April
10: following exposure to infected poultry since 2022
1: with no known animal exposure (September)
5: states with reported cases
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