Bird Flu virus Persists in Raw Milk Cheese: A ⁢Public Health Risk?

A‌ recent study by Cornell University, wiht funding from​ the US​ food and Drug Administration, reveals ‌that raw cheese produced from milk of bird flu-infected dairy cattle can harbor infectious virus for extended periods, potentially posing a risk to public​ health.

Raw Milk Cheese ⁤and H5N1 Virus

Raw milk cheeses are crafted without pasteurization, a process that typically eliminates⁤ harmful pathogens. This new research ​raises concerns​ about the ⁢stability of‌ the‌ H5N1 virus in these products.

In ⁤an interview, Kennedy stated, “The disease is not passed ​through⁣ food, ⁣so you cannot get it – as far as we know, you cannot get it from an egg or milk or meat from an infected animal.”‌ However, this statement is only ‌partly accurate.

While⁣ there have been no confirmed reports of people contracting bird flu from contaminated foods like raw milk cheese,​ it’s known that cats and ⁣other animals have ‍been infected via raw cow’s milk and raw pet food. Furthermore, there have been at least three confirmed human‌ infections where the⁣ source of exposure to the H5N1 virus remained undetermined.

Dairy workers have been infected by ⁣getting splashed⁤ with raw milk in their⁣ faces or⁢ eyes.

According to Diel, it’s “still not entirely clear whether ⁣humans ⁢can be infected by eating or drinking contaminated food,” emphasizing ⁤that his study wasn’t specifically designed to address this question.

However, Diel added, “I do think it is possible. There is a risk of infection… ‍It obviously depends ‍on the dose, how​ much of‌ that contaminated product is ‍ingested.”

The risk may also vary depending on the specific viral strain ⁤present in the milk or cheese. The‌ study examined the‍ B3.13 virus, which initially ‍infected US cattle in March 2024 and caused mild illness ⁢in humans. A newer strain,‌ D1.1, linked⁣ to more severe human cases, has also been⁤ found ⁤in cattle, further⁣ elevating the potential risk.

Study Methodology and Findings

The researchers created mini cheeses using milk⁢ spiked with the ⁣H5N1 virus,testing three⁣ pH levels: 6.6, 5.8, and 5.0 (the most acidic). They then assessed the cheeses over time to determine if‍ any infectious virus ​remained, using ⁢injections into⁤ fertilized⁤ chicken‍ eggs as the “gold‍ standard” test.

The study​ revealed that “levels of the‍ virus remained high​ for the first seven days” and then decreased⁢ slightly in cheeses with ‌pH levels⁢ of 6.6 ‌and 5.8. Importantly, “the virus remained infectious for the⁣ full ⁣two-month aging period,” demonstrating its remarkable stability.

These findings were corroborated by real-world samples of ⁢raw milk cheese from a farm with bird ​flu-infected cows. These samples also showed high virus levels and sustained infectiousness over two months.

“Our⁢ study demonstrates that HPAI H5N1 virus exhibits remarkable stability throughout the cheese making process,” the authors​ wrote in their preprint study.

However, the study indicated that increasing the acidity of ⁢raw milk cheese might‍ neutralize the virus. No ⁣live virus was⁣ detected in cheese produced at pH 5.0. Previous research has ⁢also confirmed ‌that standard pasteurization⁣ methods effectively inactivate the virus.

Expert Opinions ‌and FDA Response

Experts concur that the study ‍aligns with existing knowledge about the virus’s stability in milk.

Dr. Seema Lakdawala, an ‌associate ⁢professor of⁣ microbiology and immunology at Emory University, stated, “We have also observed that milk can change the pH needed to ⁣inactivate the virus.”

Lakdawala added, “we and others‌ have ‌repeatedly observed ​that milk will prevent the degradation of the virus on surfaces, and it increases the pH⁤ stability, such that a much lower pH than normal‍ is⁢ needed to inactivate ⁤the virus.”

The​ FDA has acknowledged the study’s findings and shared preliminary results from its ongoing raw cheese sampling study.

The FDA sampling study, initiated in December, has ⁣analyzed 110 cheese samples ‌from stores nationwide. To date,⁣ 96 samples tested negative via PCR (polymerase chain reaction), suggesting they were‍ likely made with ‍uncontaminated milk. Results for the remaining 14 samples are pending.

The ‍statement said, “the FDA is⁣ continuing to work with Federal and ⁤state partners to ⁤address the​ ongoing outbreak‌ of HPAI A ⁤(H5N1) in dairy cattle. ​The⁤ FDA has sampled a total of ⁢464 pasteurized dairy products, including milk cheese butter and ice cream, all were negative for viable H5N1. In addition, multiple research studies have confirmed‌ that pasteurization inactivates ​the virus.”

Conclusion:⁣ Vigilance and Safe​ Practices

experts emphasize the importance​ of⁢ ongoing surveillance and avoiding raw milk products.

“This is another⁤ reason we should push to ensure there is no bird flu​ in milk products ⁣and only consume pasteurized dairy products,” Lakdawala concluded.