Raw milk is milk that has not been pasteurized, meaning it goes from the animal to the bottle without being heated to kill bacteria. While all milk starts out “raw” after milking, the vast majority of milk sold in stores is pasteurized by passing thin streams of milk past very hot water on the other side of a metal plate, reaching at least 161°F for at least 15 seconds. Raw milk skips this step entirely, preserving its original microbial and enzymatic profile but also retaining any pathogens that may be present.
How Raw Milk Differs From Pasteurized
Every glass of milk begins the same way. After milking, raw milk is refrigerated and stored separately from milk destined for pasteurization. At that point, the paths diverge. Pasteurized milk goes through rapid heating that kills virtually all bacteria, both harmful and beneficial. Raw milk stays as it was, with its full community of microorganisms intact.
This distinction matters because pasteurization was introduced specifically to address foodborne illness. Before it became standard practice in the early 20th century, milk was a common vehicle for diseases like tuberculosis and typhoid fever. Today, raw milk advocates argue the process also destroys beneficial components of the milk, which is partly true, though the practical significance of those losses is smaller than many people assume.
Nutritional Differences Are Modest
A meta-analysis of 40 studies found that pasteurization does reduce levels of certain vitamins. Vitamins B1, B2, C, and folate all decreased after heat treatment. Vitamins B12 and E also dropped, while vitamin A actually increased. Vitamin B6 showed no significant change.
These numbers sound concerning in isolation, but the researchers concluded the overall effect on milk’s nutritional value was minimal. The reason: most of the affected vitamins are naturally present in milk at relatively low levels to begin with. You’re not relying on milk as your primary source of vitamin C or folate. The one exception worth noting is vitamin B2 (riboflavin), since milk is a meaningful dietary source of it, and pasteurization does cause a small but measurable decline.
In practical terms, the nutritional gap between a glass of raw milk and a glass of pasteurized milk is not large enough to meaningfully change your diet. The protein, fat, calcium, and calorie content remain essentially the same.
The Allergy and Asthma Connection
The most scientifically interesting claim about raw milk involves childhood allergies. For over a decade, researchers have studied the “farm effect,” the observation that children who grow up on farms have lower rates of allergies and asthma. Raw milk consumption appears to be one piece of that puzzle.
A study called ALEX found that children who consumed unpasteurized farm milk in their first year of life were less likely to develop asthma or allergic sensitization at school age. This held true even for children who didn’t live on a farm, though exposure to farm stables strengthened the effect. The PASTURE study confirmed that regular consumption of unpasteurized milk was inversely related to asthma onset by age 6. Other research found raw farm milk in early life protected not only against allergies and asthma but also against rhinitis, ear infections, and other respiratory infections.
The biological mechanism may involve regulatory immune cells. Farm milk exposure has been associated with increased numbers of a specific type of regulatory T cell that helps calibrate the immune system, reducing the overreactions that drive allergic disease. These findings are consistent and replicated across multiple European studies, making this one of the more credible health claims associated with raw milk. That said, researchers have not yet isolated exactly which component of raw farm milk drives the effect, and it remains unclear whether commercially sold raw milk would produce the same benefit as milk consumed fresh on a farm.
Raw Milk Does Not Help Lactose Intolerance
One of the most popular claims about raw milk is that lactose-intolerant people can drink it without symptoms. The theory is that raw milk’s natural bacteria, particularly lactobacilli, help break down lactose during digestion. It’s a reasonable hypothesis, since unpasteurized yogurt with live cultures genuinely does improve lactose digestion compared to pasteurized yogurt.
But a randomized controlled trial tested this directly and found no benefit. Adults with confirmed lactose malabsorption drank raw milk, pasteurized milk, and soy milk over multiple days. Raw milk did not reduce lactose malabsorption by any objective measure, and symptom severity was identical between raw and pasteurized milk. The researchers concluded that the data “do not support widespread anecdotal claims that raw milk reduces the symptoms of lactose intolerance.” If you’re lactose intolerant, switching to raw milk is unlikely to help.
Bacteria in Raw Milk: Good and Bad
Raw milk does contain beneficial bacteria, including Lactobacillus and Bifidobacterium, two genera commonly used as probiotics. Research tracking raw milk microbiota over 12 months found these two groups had a strong positive correlation, meaning they tend to thrive together. The microbial community in raw milk varies by season, farm, and even weather conditions.
The problem is that raw milk also harbors dangerous pathogens at meaningful rates. A systematic review of U.S. raw milk samples collected between 2000 and 2019 found Campylobacter in 6.0% of bulk tank samples, Listeria in 4.3%, Shiga toxin-producing E. coli in 4.3%, and Salmonella in 3.6%. These are not rare contaminants. Even well-managed farms with healthy herds can produce milk carrying these organisms, because many of them live naturally in the cow’s gut or environment without making the animal visibly sick.
At refrigerator temperature (about 39°F), raw milk has a shelf life of roughly 7 days before bacterial counts spike to levels associated with spoilage. By day 3, yeasts and molds begin appearing. By day 7, total bacterial counts climb into the tens of millions per milliliter and the milk starts to deteriorate. This is a much narrower safety window than pasteurized milk, which typically lasts two to three weeks refrigerated.
Outbreak and Hospitalization Rates
The clearest picture of raw milk’s risk comes from CDC data covering 2009 through 2014. Only about 3.2% of the U.S. population consumed unpasteurized milk during that period, yet unpasteurized dairy products caused 96% of all illnesses linked to contaminated dairy. Adjusted for the size of each consumer group, people who drank raw milk were 839 times more likely to get sick and 45 times more likely to be hospitalized than people who drank pasteurized milk.
On average, dairy-related outbreaks cause about 760 illnesses and 22 hospitalizations per year in the U.S., driven mostly by Salmonella and Campylobacter. The CDC estimated that if raw milk consumption were to double, outbreak-related illnesses would increase by 96%.
Bird Flu Added a New Risk Layer
Starting in 2024, highly pathogenic avian influenza (H5N1) spread through U.S. dairy herds, adding a new dimension to the raw milk safety conversation. The virus has been detected in unpasteurized milk from both visibly ill and apparently healthy cows. Pasteurization effectively kills the virus, making commercial pasteurized milk safe.
The concern with raw milk is that someone consuming it could potentially become infected if the milk contains live H5N1 virus. The virus could bind to receptors in the upper respiratory tract or reach the lungs through aspiration. The overall risk to the general public remains low, but the situation underscored a fundamental limitation of raw milk: you can’t see, smell, or taste viral contamination, and there’s no consumer-level way to test for it.
Legal Status Varies by State
Federal law prohibits selling unpasteurized milk across state lines for human consumption. Within state borders, the rules vary widely. Some states allow raw milk to be sold in retail stores. Others permit sales only at the farm where the milk was produced. A growing number of states allow “herd share” or “cow share” arrangements, where consumers buy a share of a cow and receive a portion of its milk, sidestepping direct sales regulations. A smaller number of states prohibit the sale of raw milk to consumers entirely.
The legal landscape has been shifting toward greater access in recent years, with several states loosening restrictions. If you’re looking to buy raw milk, your state’s department of agriculture will have the most current rules, since the regulatory picture changes frequently.