Raw milk is milk that comes straight from the animal and has not been pasteurized, meaning it skips the heating process that kills harmful bacteria. It’s sold by farms and, in some states, retail stores, and it has become a polarizing topic in food and health circles. Supporters point to its natural enzyme content and possible immune benefits, while public health agencies flag serious infection risks. Here’s what the evidence actually shows.
How Raw Milk Differs From Store-Bought Milk
Pasteurization heats milk to a high temperature for a set period, killing bacteria like Salmonella and Campylobacter. It also inactivates certain natural enzymes. Two of the most studied are alkaline phosphatase, which breaks down at around 60°C (140°F), and lactoperoxidase, which survives standard pasteurization but is destroyed at higher temperatures. Proponents of raw milk argue these enzymes aid digestion and boost immune function, though clinical evidence for those claims is thin.
Most store-bought milk is also homogenized, a separate mechanical process that breaks fat globules into smaller, uniform particles so the cream doesn’t rise to the top. Raw milk is almost never homogenized. That’s why it separates in the fridge, with a visible cream line near the cap.
Nutritional Differences Are Smaller Than You’d Think
A systematic review and meta-analysis comparing raw and pasteurized milk found that pasteurization does reduce some vitamins. Vitamins B1, B2, C, and folate all showed statistically significant decreases after heat treatment. Vitamins B12 and E also declined, while vitamin A actually increased. Vitamin B6 showed no significant change.
These losses sound concerning in isolation, but context matters. Milk is not a primary dietary source of vitamin C or folate for most people. The nutrients milk is best known for, calcium, protein, and fat, are not meaningfully affected by pasteurization. So the nutritional gap between raw and pasteurized milk is real but narrow, and unlikely to matter if you eat a reasonably varied diet.
The Allergy and Asthma Research
Some of the most intriguing data on raw milk comes from large European studies on farm children. The PARSIFAL study found that drinking unpasteurized farm milk in the first year of life was associated with lower rates of childhood allergic conditions. A separate analysis found that regular consumption of unpasteurized milk in infancy was protective against asthma in both farming and non-farming families, with farming children seeing the strongest effect (70% lower odds of an asthma diagnosis).
One particularly telling finding: when researchers tested boiled farm milk against raw farm milk, only the raw version showed a protective association with asthma. Boiled farm milk had no measurable benefit. This suggests something in raw milk, likely heat-sensitive proteins or bacterial compounds, plays a role in immune development during early childhood.
There’s an important caveat. These studies are observational, meaning they track patterns but can’t prove cause and effect. Children raised on farms differ from urban children in dozens of ways beyond their milk. Researchers have tried to control for those variables, but the possibility of confounding factors remains. No one has yet run a large randomized trial giving raw milk to infants, partly because of the infection risks involved.
Raw Milk and Lactose Intolerance
One of the most common claims about raw milk is that people who can’t tolerate regular milk do fine with it. The idea is that natural enzymes or bacteria in raw milk help break down lactose before it causes symptoms. A randomized controlled trial put this directly to the test, enrolling 16 adults with confirmed lactose malabsorption and having them drink both raw and pasteurized milk in a crossover design. The result: no difference. Symptom severity for gas, cramping, bowel sounds, and diarrhea was statistically identical between the two milks, even at the highest dose. Raw milk did not reduce lactose malabsorption or its symptoms.
The Infection Risk Is Not Theoretical
Only about 3.2% of the U.S. population drinks unpasteurized milk, and roughly 1.6% eats unpasteurized cheese. Yet these products account for 96% of all illnesses tied to contaminated dairy. Across the country, dairy-related outbreaks cause an average of 760 illnesses and 22 hospitalizations per year, driven mostly by Salmonella and Campylobacter. The math is straightforward: a small share of consumers absorbs nearly all the risk.
Contamination can come from the cow’s udder, the skin around it, the milking equipment, or the hands of the person milking. Even spotlessly clean farms can’t eliminate every source. Bacteria that cause no illness in a healthy cow can be dangerous to humans, particularly young children, pregnant women, older adults, and anyone with a weakened immune system.
Shelf Life and Storage
Pasteurized whole milk typically lasts 12 to 14 days in a refrigerator kept below 4°C (39°F). Raw milk has a considerably shorter window, often around 7 to 10 days under ideal conditions, and it’s far less forgiving of temperature fluctuations. If your fridge runs warm or the milk sits out during a meal, bacterial counts can climb fast. Storing it toward the back of the fridge, where the temperature is most stable, helps.
Because there’s no heat treatment acting as a safety net, temperature control from the moment of milking through transport and home storage is critical. Many raw milk producers recommend consuming it within a few days of purchase.
Where It’s Legal in the U.S.
Raw milk sales are legal in 32 states, though the conditions vary widely. Some allow it on retail store shelves, others restrict sales to the farm itself, and a few only permit “herdshare” arrangements where you buy a share of a cow and receive milk as a co-owner. Eighteen states ban the sale of raw milk entirely. Federal law prohibits its sale across state lines, so even in states where it’s legal, the milk has to be produced locally.
If you’re looking for raw milk, your state’s department of agriculture website will list current regulations. In states that allow it, farms selling raw milk are generally required to meet specific testing and labeling standards, though enforcement varies.