The most recent bird flu (H5N1) outbreak has spread to dairy cattle, spurring a wave of misinformation about raw milk vs. pasteurized milk, disease spread and immunity, and the perceived health benefits of raw milk. Here's what you need to know.

What is raw milk?

Raw milk is unpasteurized, or milk that has not been heated to temperatures that kill pathogens like Salmonella, E. coli, Listeria, or other harmful bacteria and viruses. Consuming raw milk can cause vomiting, diarrhea, fever, body and abdominal pains, and headache—but it may also cause chronic, severe, and life-threatening symptoms. Infants, children, and pregnant people experience higher risks from foodborne illnesses; E. coli O157, for example, is more likely to cause kidney failure in infants and children than in adults, but immunocompromised and elderly adults are also at greater risk than healthy younger adults.

Pasteurization and public health

Pasteurized milk is chilled raw milk that is briefly heated to temperatures sufficient to kill bacteria. The pasteurization process was invented by Louis Pasteur in 1864 and has been used in commercial milk production in the US for many decades. Following pasteurization, the milk is cooled, mixed with the appropriate milkfat content (which is removed during heating), homogenized to prevent separation, and often fortified with Vitamins A and D before being packaged for sale.  

Mandatory pasteurization has improved America’s food system by reducing disease outbreaks. In the US, milk‐borne diseases were responsible for 25 percent of all foodborne illness outbreaks in 1938; by 2016, milk and dairy products were responsible for less than 1 percent of foodborne illness outbreaks.

The CDC, FDA, USDA, American Medical Association, American Academy of Pediatrics, American Public Health Association, National Environmental Health Association, National Public Health Information Coalition, and other health organizations advise against drinking raw milk, particularly for infants, children, pregnant or elderly people, and the immunocompromised.  

Raw milk and illness risk

H5N1, the most recent avian flu variant, has infected dairy cattle. Pasteurization kills the virus, but there is a chance that the live virus could survive in raw milk and transmit infection. So far, however, the only human cases of infection with H5N1 have been in dairy workers.

Sales of raw milk, though, have not been negatively impacted by the outbreak. In fact, they continue to climb: data from NielsenIQ indicate sales of raw milk increased 20 to 65 percent since last year, showing no signs of flagging in the midst of the dairy cattle outbreak.  

But H5N1 isn’t the only infectious disease that can be present in raw milk: it’s also a source of Salmonella, Campylobacter, and E. coli, germs that can cause hospitalization, long-term complications, and death. Children under 5, adults over 65, pregnant people, and those with weakened immune systems are especially vulnerable.  

Social media and unfounded health claims

Despite decades of research pointing to raw milk as a vector for foodborne illness and failing to identify meaningful differences in the nutritional values of raw and pasteurized milk, influencers (in conservative circles as well as the organic and alternative “wellness” spheres) have touted unpasteurized dairy as a healthy way to achieve immunity against H5N1 and other viruses; “cure” lactose intolerance, asthma, and allergy; prevent osteoporosis; improve gut health; aid digestion; and many other unfounded claims.

The FDA has published a fact sheet that debunks each of these misconceptions, and the CDC has issued updated guidance for healthcare providers about raw milk and avian flu. Nevertheless, raw milk continues to grow in popularity, presenting an opportunity for viruses and bacteria to threaten public health.

Learn more at NutritionAction:Can you become more tolerant of lactose?

Lax regulatory oversight makes raw milk easy to buy

Because consuming raw milk poses a significant public health risk, the FDA banned the sale and transport of unpasteurized milk, cheese, and other raw dairy products packaged for human consumption across state lines in 1987. However, no state or federal laws prohibit the purchase or consumption of raw milk, and many states allow intrastate sales of local raw milk, so it’s not terribly difficult to find. Since 2004, the FDA has issued only a handful of warning letters to producers who cross state lines to sell raw dairy.  

“Selling raw milk is like marketing a car without a seatbelt,” says Sarah Sorscher, director of regulatory affairs at CSPI. “You may never have an issue, but if you have enough people taking that risk consistently, you know it will cost lives. If that’s something you can avoid, why wouldn’t you?”

Raw milk offers no significant nutritional benefits

There are no health benefits to consuming raw milk instead of pasteurized milk or a non-dairy alternative. In fact, since the risks of foodborne illness are significantly higher with raw milk, vulnerable groups seeking a cure for allergy or disease may find themselves with chronic health complications from illness instead of a health improvement. Nutritionally, raw and pasteurized milk are the same, though pasteurized milk has the advantage of typically being fortified with vitamin D, which is only present in negligible amounts in raw milk.

Children should not drink raw milk, and when choosing pasteurized milk, opt for fat-free or low-fat milk after age 2. Saturated fat is well-established to contribute to elevated LDL (“bad”) cholesterol, which is associated with an increased risk of heart disease. The 2020 Dietary Guidelines Advisory Committee found strong evidence that diets lower in saturated fat and cholesterol during childhood result in lower levels of LDL cholesterol throughout childhood. 

Learn more at CSPI News:Why milk served in schools is always low-fat or nonfat