Bird flu latest: FDA raises raw milk risks awareness, studies pasteurization effectiveness

Raw milk consumption has increased 25% over the past year in the US, according to NielsenIQ. The market research agency’s data also shows that consumption continued to increase in the weeks since the first case of avian influenza in cattle was announced at the end of March 2024, with weekly raw milk sales rising between 21% and 65% from the end of March to the middle of May year on year.

This behavior is flying in the face of official advice, with federal agencies such as the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) having warned shoppers to steer clear from raw milk while experts investigate the first ever outbreak of avian influenza in dairy cattle in the US. In addition, both the FDA and the CDC hold long-standing views against raw milk consumption, while FDA mandates that only pasteurized milk can be sold across state lines.

So why are consumers buying more raw milk during the ongoing influenza A(H5N1) outbreak that has now affected more than 129 herds in 12 states?

Lack of evidence is fueling speculation

For one, experts have so far been unable to provide conclusive evidence whether consuming raw milk increases the risk of transmitting the virus to humans. Veterinarians have found that infected dairy cows shed large amounts of the virus in milk, and there is evidence that pasteurization inactivates it alongside other harmful pathogens. This is also why the FDA found DNA traces of the virus in commercial milk, but no ‘live’ virus.

At the same time, a group of veterinarians discovered that domestic cats that lived on farms with reported infections had died after consuming raw milk, suggesting a potential link between raw milk consumption and infection. However, there is no solid evidence of how raw milk consumption impacts the risk of transmission in humans, with the only three cases of the strain in humans having been recorded in dairy farm workers that had been in close contact with infected animals.

Nevertheless, agriculture secretary Tom Vilsack has said that even a splash of infected milk could transmit the virus. “As producers, USDA scientists, and veterinarians looked carefully at H5N1, including through detailed epidemiological analysis, we learned that the H5N1 virus concentrates in the udder of sick cows and in the cow’s milk, which can contain high loads of the virus,” he wrote in an op-ed released to the press. “That means even just a small splash of milk can spread the disease.”

But the lack of conclusive evidence that demonstrates if unpasteurized milk consumption leads to virus transmission in humans is why raw milk producer organizations such as the Raw Milk Institute have called federal agencies’ warnings ‘fearmongering’.

“The FDA acknowledges that ‘there is limited information available about the transmission of bird flu in raw, unpasteurized milk,’” wrote Mark McAfee,  chairman and president of the Raw Milk Institute board and founder of McAfee Farms and Organic Pastures Dairy Co., LLC. “Then they go on to use the same fearmongering tactics they’ve been using for decades against raw milk, despite the fact that there is now ample evidence that raw milk can be carefully produced as a low-risk food.”

Raw milk isn’t a low-risk food in the FDA’s books, however. The regulator treats pasteurized dairy products including milk, cheese, cream and yogurt as low-risk, with any unpasteurized dairy considered high-risk.

Raw milk is available to consumers – in some states

Another factor that may be driving raw milk sales is that in some state jurisdictions, dairy producers are allowed to market unpasteurized milk for human consumption. In states such as California, Maine, New Hampshire, New Mexico and Pennsylvania, raw milk can be purchased in retail stores as well as from the farmer, who may not even need to hold a licence.

Raw milk producers also argue that they are well-prepared to detect avian influenza in cattle as many already monitor their herds for illness and test their milk for the presence of pathogens. For example, producer Raw Farm LLC of Fresno, California, is enrolled in the monitored herd pilot program ran by the California Department of Food and Agriculture and was told in a letter from May 28 that its herd was ‘in good standing of current program requirements’.

Dairy farmers that focus on pasteurized dairy have been urged to voluntarily test their herds, with the USDA offering financial incentives to those that take a more proactive approach. Secretary Vilsack has also highlighted that ‘improved biosecurity is the key to limiting the spread of H5N1 to keep animals, workers and farm operations safe’.

“USDA has many ways to support producers, including the ability to help producers pay for, enhanced biosecurity plans, free H5N1 testing for dairy cattle, free shipping to send test samples to the lab, free veterinary costs, free personal protective equipment, and more,” he explained.

“Moreover, for producers that have H5N1 in their herd, USDA intends to introduce a program through the Emergency Assistance for Livestock, Honeybees, and Farm-Raised Fish Program – better known as ELAP – that is being developed to compensate eligible producers with positive herds who experience loss of milk production. By statute, ELAP is authorized to pay eligible producers 90% of the value of losses.

“The program would pay an amount per cow, for a set period of time. Additionally, for producers who want to help contain the disease and reduce the burden on their operations, USDA recently announced a Voluntary H5N1 Dairy Herd Status program.”

Know raw’s risks, says FDA in new consumer-focused campaign

In a bid to get its point across to dairy consumers, the FDA has launched an awareness campaign that spells out the risks of consuming raw milk.

In a press release​ dated June 25, the agency stated: “Milk and milk products like yogurt and cheese have many healthy nutrients. However, raw milk, also known as unpasteurized milk, can contain harmful germs that could lead to foodborne illnesses. Protect yourself from illnesses caused by unpasteurized milk and milk products during National Dairy Month by reading about raw milk and practicing safe food handling.”

The FDA goes on to bust a number of ‘milk myths’ often claimed by raw milk aficionados, such as that pasteurization reduces milk’s nutritional value or causes lactose intolerance (it does not, the FDA says).

Pasteurization’s effectiveness in sharp focus

On June 25, the FDA also released details into its research into the effectiveness of pasteurization and other methods that can inactivate the H5N1 virus.

“We have been actively engaged in conducting studies using continuous flow pasteurization equipment, reflective of those in commercial use, to help confirm pasteurization parameters that are effective at inactivating H5N1 HPAI virus during milk processing. These ongoing studies will provide the information to validate evidence of the effectiveness of pasteurization in ensuring that no viable HPAI H5N1 virus is present in the commercial milk supply. The agency is committing to sharing results from these ongoing studies in the near future,” the agency said in a statement.

There will be four focus area of research. These include:

• pre-pasteurization milk sampling, i.e. testing pooled raw milk samples to determine the level of virus present in milk before pasteurization;
• bench-top thermal inactivation kinetics studies, which will estimate the precise time and temperature required to inactivate the virus;
• continuous flow pasteurization studies, which will help to confirm the parameters at which the virus is inactivated during commercial pasteurization;
• raw milk cheese ageing, which will assess if the virus can survive during raw cheese ageing.

The FDA has also launched a second nationwide sampling survey of dairy products available in retail. The first review did not detect viable virus in 297 retail samples of dairy and milk products, but in the second one, only 155 products will be tested, including aged raw milk cheese, pasteurized milk and pasteurized cheeses, cream cheese, butter and ice cream.