What Pasteurization Destroys
Standard pasteurization heats milk to 161 degrees F for 15 seconds (HTST) or 280 degrees F for 2 seconds (UHT). This kills pathogens effectively, but it also destroys or diminishes several components [4]:
- Enzymes: Lactase (which helps digest lactose), lipase (which helps digest milk fat), and phosphatase (which aids mineral absorption) are all denatured by heat [4]. This is significant because many people who consider themselves "lactose intolerant" report being able to drink raw milk without symptoms -- the naturally present lactase may assist digestion.
- Beneficial bacteria: Raw milk contains a diverse community of Lactobacillus, Bifidobacterium, and other probiotic organisms that are eliminated by pasteurization. These bacteria may support gut health and immune function.
- Whey proteins: Heat-sensitive whey proteins, including immunoglobulins, lactoferrin, and lactoperoxidase, are partially or fully denatured. These proteins have antimicrobial and immune-modulating properties [2].
- Fat-soluble vitamins: Vitamins A, D, E, and K are partially reduced. The extent varies by pasteurization method, with UHT causing the greatest losses.
The Allergy and Immunity Connection
Some of the most compelling research on raw milk comes from European studies on farm children. The GABRIELA study found that children who consumed raw farm milk had significantly lower rates of asthma, hay fever, and atopic sensitization compared to children who drank pasteurized milk [1]. Loss et al. (2015) followed up with evidence suggesting that heat-sensitive whey proteins in raw milk -- particularly beta-lactoglobulin and alpha-lactalbumin -- may be responsible for these protective effects [2].
These findings are observational and may be confounded by the broader "farm effect" (exposure to animals, microbes, and diverse allergens). But the consistency of results across multiple European cohorts is noteworthy.
A2 vs A1 Casein
A separate but related issue is the type of casein protein in milk. Most conventional dairy cows (Holsteins) produce A1 beta-casein, which during digestion releases a peptide called BCM-7 (beta-casomorphin-7). Some research suggests BCM-7 may contribute to digestive discomfort, inflammation, and other issues in sensitive individuals.
Older heritage breeds -- Jerseys, Guernseys, Brown Swiss, and most goats and sheep -- predominantly produce A2 beta-casein, which does not release BCM-7. Many people who struggle with conventional milk find they tolerate A2 milk well. Raw milk from small farms often comes from these heritage breeds, which may partly explain why some people tolerate raw milk better than store-bought.
The Real Safety Risks
Raw milk can carry dangerous pathogens, and this risk should not be dismissed [3]:
- Campylobacter: The most common pathogen found in raw milk outbreaks.
- E. coli O157:H7: Can cause hemolytic uremic syndrome, a life-threatening condition particularly dangerous for children.
- Listeria monocytogenes: Especially dangerous for pregnant women, the elderly, and immunocompromised individuals.
- Salmonella: Less common but documented in raw milk outbreaks.
Langer et al. (2012) documented 73 outbreaks linked to nonpasteurized dairy products in the U.S. between 1993 and 2006, resulting in 1,571 illnesses, 202 hospitalizations, and 2 deaths [3]. The risk is real.
However, context matters. These outbreaks were disproportionately linked to large-scale or poorly managed operations. Small, dedicated raw milk dairies that practice rigorous testing, sanitation, and herd management have much lower risk profiles. The sourcing question is everything -- knowing your farmer, understanding their testing protocols, and verifying that the dairy is specifically set up for raw milk production (not simply selling unpasteurized milk as an afterthought).
Legal Status
Raw milk legality varies dramatically by state. Some states allow retail sales in stores, some permit farm-gate sales only, some allow herdshare arrangements (where you buy a share of the cow), and some ban all raw milk sales. This patchwork reflects the genuine tension between consumer choice and public health policy.
Evidence Review
Loss et al. (2011) studied over 8,000 children across rural areas in Austria, Finland, France, Germany, and Switzerland as part of the GABRIELA study [1]. They found a strong inverse association between raw farm milk consumption and asthma, atopy, and hay fever -- children who drank raw milk had roughly 40% lower odds of asthma and 25% lower odds of atopic sensitization. This built on earlier findings from the PARSIFAL study, which showed similar protective effects.
Loss et al. (2015) investigated the mechanistic basis for these observations, identifying heat-sensitive whey proteins as likely mediators of raw milk's protective effects [2]. When milk was heated, the protective association disappeared, suggesting that the immune benefits are linked to components that pasteurization destroys. The authors proposed that intact whey proteins may modulate immune development through effects on regulatory T cells and gut-associated lymphoid tissue.
Langer et al. (2012) provided the most comprehensive U.S. epidemiological data on raw milk safety, analyzing CDC outbreak surveillance data from 1993 to 2006 [3]. They found that states permitting raw milk sales had more outbreaks than states that prohibited them. However, it is worth noting that per-serving risk calculations are difficult because total raw milk consumption is not precisely measured, and the absolute number of illnesses (1,571 over 14 years in a population of millions of raw milk consumers) is relatively small compared to outbreaks from other food sources like leafy greens and poultry.
Chen and Nawar (1991) documented the thermal sensitivity of milk lipase and other native enzymes, showing that standard pasteurization temperatures are sufficient to inactivate lipase, phosphatase, and other enzymes that are present and active in raw milk [4]. These enzymes facilitate fat digestion and mineral absorption, and their destruction may contribute to the digestive difficulties some people experience with pasteurized dairy.
Where the evidence stands: The nutritional and immunological differences between raw and pasteurized milk are supported by credible research, particularly the European farm-child studies. The safety risks are also real and documented, though they are heavily influenced by sourcing and management practices. This is a topic where individual risk tolerance, access to reputable farms, and personal health status all factor into the decision. Pregnant women, young children, the elderly, and immunocompromised individuals face the highest risk from potential pathogens, and mainstream medical guidance recommends they avoid raw milk.