Is Raw Milk Safe? Benefits, Risks, and Scientific Evidence

What is Raw Milk?

Raw milk, also known as unpasteurized milk, refers to milk that has not undergone the pasteurization process. It can come from various sources, including cows, goats, sheep, and even camels.

Image: Milking Cow

Credit: Shatterstock

A brief history

Pasteurization, developed by French scientist Louis Pasteur in 1864, is now a widely used method for preserving liquid foods. The process involves heating the liquid to at least 60°C (140°F) for a specific period of time to destroy harmful pathogens and extend shelf life.

Originally, Pasteur devised this method to address spoilage issues in wine [1]. It was later adapted for use in a variety of other products, including beer, milk, fruit juices, syrups, vinegars, eggs, and more.

Image: Louis Pasteur

Credit: Science History Institute

Pasteurization and the germ theory

Germ theory is one of the currently accepted theories, based on the idea that diseases are caused by tiny living organisms, germs, such as bacteria, viruses, and fungi, that invade the host's body and interfere with its normal functions. The widespread use of pasteurization today is directly linked to the development of germ theory. Louis Pasteur demonstrated that wine spoilage was caused by microbial contamination, not by spontaneous generation as many believed at the time [1]. He proved that these microbes came from the environment, rather than appearing out of nowhere [2].

This breakthrough laid the foundation for modern disease prevention by emphasizing the control of exposure to harmful microorganisms. It led to successful efforts in limiting the spread of bacterial diseases such as E. coli, bovine tuberculosis, and brucellosis, and was later applied to combat foodborne pathogens like E. coli O157:H7, Campylobacter, Listeria, and Salmonella. These principles continue to justify the use of pasteurization in food preservation, especially in the ongoing public debate surrounding the safety and regulation of raw milk.

Pasteurized procedures [3]

Raw milk is collected from milk-producing animals and immediately cooled to around 4°C (39°F) to slow bacterial growth. It is then transported in sanitized stainless-steel tanks to dairy processing facilities.

At the plant, the milk is filtered to remove particulates and somatic cells. Fat content may be standardized at this stage to produce whole, low-fat, or skim milk. Centrifugal clarifiers are typically used to remove sediment and other impurities.

Graph: Microscopic images (1250 × magnification) of fat globules in raw milk sample, before and after homogenization

(a) fat globules in raw milk,

(b) fat globules in the raw milk sample after 120 s of ultrasonic homogenization,

(c) fat globules in the raw milk sample after 1200 s of ultrasonic homogenization.

The black scale bar in the bottom‐right corner represents 10 μm.

Credit: Ultrasound assisted processing of milk: Advances and challenges

Homogenization, while common, is not always required. This process breaks down fat globules to prevent cream separation, creating a uniform texture and appearance. It is widely used for standard milk products, but may be omitted in cream, butter, or certain organic and artisanal milks where natural separation or a richer texture is preferred.

Pasteurization methods vary based on temperature, heating duration and products. Below is an example of the pasteurization standard used for milk.

Table: Details of Milk Pasteurization

Credit: International Dairy Foods Association

After pasteurization, the milk is once again cooled to 4°C (39°F), making it ready for bottling, further processing, or commercial distribution.

Refrigerated pasteurized milk generally has a longer shelf life than raw milk. Typically, milk processed using HTST pasteurization lasts about 2–3 weeks under refrigeration. In contrast, UP milk has a longer shelf life, usually around 2–3 months. When processed at even higher temperatures and packaged aseptically, milk can remain shelf-stable for up to 9 months without refrigeration.

Graph: Fat globules in raw milk magnified 175 times

Graph: Fat globules in pasteurized, unhomogenized milk, magnified 175 times

Graph: Fat globules in pasteurized, homogenized milk, magnified 175 times

Graph: Fat globules in ultra-pasteurized, homogenized milk, magnified 175 times

Credit: Microphotography of Raw and Processed Milk

Traditional vs. modern usage

Consuming milk from other mammals stands out as one of humanity’s most distinctive and conventional eating habits, with evidence tracing back 6,000 years through calcified dental plaque from Neolithic British and African populations, and milk fats and lipids found on pottery shards from early farming sites in Eastern Europe dating to approximately 7000 years ago [4] [5] [6]. Milk consumption was regular among early farmers and pastoralists who domesticated dairy animals, primarily cattle, sheep, and goats. As these domesticated animals spread across different regions, so too did the practice of dairy consumption, adapting to local cultures and environments.

Raw milk is commonly used in the production of various dairy derivatives, including cheese, butter, and cream, not only for its nutritional properties but also to enrich the sensory and cultural aesthetics of human diets.

For example, Camembert, a moist, soft, creamy, surface-ripened cow’s milk cheese originating from France, was traditionally made using raw milk. Today, the AOC (Appellation d'Origine Contrôlée) certified variety Camembert de Normandie, which accounts for roughly 10% of total Camembert production, is legally required to be made exclusively from unpasteurized milk.

Image: Baked camembert with garlic bread

Credit: BBC

Other traditional foods also rely on raw or lightly processed milk. Syllabub, a classic British dessert, is made by curdling cream or milk with an acidic liquid such as wine or cider, resulting in a frothy, tangy-sweet treat [7]. Yak butter, a staple among herder communities, is produced by fermenting yak milk overnight and then churning it into a dense, nutrient-rich butter used in cooking, tea, and ritual offerings.

Image: Yak Butter Tea

Credit: Tibetpedia

Mainstream vs. Alternative Views

Mainstream

Raw milk is widely recognized to potentially contain pathogenic bacteria and parasites associated with foodborne illness, which include tuberculosis, diphtheria, typhoid, Campylobacter, Listeria, Brucella, E. coli (especially E. coli O157:H7), Salmonella, Streptococcal infections, Cryptosporidium [8] [9]. These pathogens have caused documented outbreaks linked to consumption of raw milk and its products in recent decades, in both developed and developing countries [10] [11] [12].

Many countries consider raw milk unsafe and regulate or ban its sale. For instance, Singapore and Canada completely ban commercial sales of raw milk for human consumption [13] [14]. Others, including Germany, Norway, Finland, the UK (except Scotland), New Zealand, Australia, and certain U.S. states, allow direct purchases from farms or retail sale, but these are often accompanied by explicit warning labels and strict production standards [15] [16] [17]. In some Asian countries, Ireland, and parts of South Africa, production and sale are permitted under specific conditions [18] [19]. Raw milk used for private consumption, animal or pet feeding, or for making products like soap is often legal but sometimes criticized as exploiting loopholes in the law [9].

Image: Raw Milk Legal States 2025

Credit: World Population Review

What the science says

Epidemiological data have highlighted the public health risks associated with raw milk consumption. From 2007 to 2020, 83% of hemolytic uremic syndrome (HUS) cases linked to E. coli O157:H7 infection in North America were attributed to 20 outbreaks involving raw dairy, 14 of which were specifically linked to raw milk consumption [20].

Concerns have also emerged around raw milk as a vector for viral infections. Highly Pathogenic Avian Influenza (H5N1) has been detected in raw milk from infected dairy cattle, with studies showing that viral RNA can persist for at least 57 days at 4°C without degradation [21] [22]. In contrast, pasteurization effectively eliminates detectable virus levels and significantly reduces RNA concentration [21]. Other pathogens demonstrate varied behavior in raw milk: salmonella levels tend to decline, E. coli O157:H7 and listeria often persist, and campylobacter generally dies off during refrigeration [23]. In Iran, raw milk samples revealed high prevalence rates of norovirus GI (34.95%) and GII (7.72%), as well as rotavirus (14.6%), astrovirus (12.8%), and tick-borne encephalitis virus (21.3%) [24]. Hepatitis A virus (HAV) has also been found in raw milk and raw dairy products across regions such as Egypt and Iran, with reported prevalence ranging from 1.5% to 25% [24] [25]. Documented outbreaks linked to HAV-contaminated raw milk further underscore its potential as a public health threat.

While pasteurization greatly reduces the risk of milkborne disease, outbreaks can still occur due to improper pasteurization, post-pasteurization contamination, or the growth of heat-resistant or cold-growing pathogens like Listeria during refrigeration. For example, in 1985, contaminated pasteurized milk from a dairy plant in Illinois sickened thousands across multiple US states due to Salmonella [26]. The contamination resulted from a valve issue that allowed pasteurized milk to mix with raw milk harboring pathogens, highlighting post-pasteurization contamination risks [26]. Pasteurized products can become contaminated from equipment, personnel, or the environment after processing, emphasizing the importance of strict hygiene.

Epidemiological evidence from the United States between 2005 and 2020 shows that foods such as leafy greens, fruits, peanut butter, and oysters have caused far more deaths, illnesses, and hospitalizations than raw milk [27]. Over a 15-year period, cucumbers alone were linked to 36 deaths and 2 major outbreaks, compared with only 3 deaths and 1 outbreak associated with all types of milk combined. Older statistics further indicate that on a per-serving basis, raw milk carries about seven times the illness risk of pasteurized milk, yet deli meats, cold hot dogs, and pâté pose roughly ten times the risk of raw milk, while smoked seafood and pre-cooked shrimp present similar risks [28].

Table: Burden of illness from foodborne outbreaks for four foods over the years 2005-2020

Credit:Trends in Burdens of Disease by Transmission Source (USA, 2005–2020) and Hazard Identification for Foods: Focus on Milkborne Disease

The most affected groups in such cases were individuals with weakened immune systems, particularly children, the elderly, and pregnant women, who are especially vulnerable to foodborne pathogens. As a result, public health officials have framed raw milk as inherently hazardous, stressing its strong association with serious foodborne illnesses. Children, in particular, have been portrayed as lacking the capacity to assess such risks and thus requiring regulatory protection.

Alternative

While pasteurization played a crucial role in reducing disease outbreaks during the rise of industrial urban living, proponents like naturopathic physician Ron Schmid emphasized that raw milk had been consumed safely for centuries prior to industrialization. This historical perspective challenges the prevailing assumption that raw milk is inherently hazardous, suggesting instead that the risks are more context-dependent and manageable with proper hygiene and handling. Furthermore, the beneficial bacteria in grass-fed raw milk are suggested to inhibit harmful microbes.

Advocates like Journalist David Gumpert argue that raw milk preserves a range of beneficial components, such as enzymes, probiotics, and delicate proteins, that are often destroyed or altered during pasteurization. They claim that these living elements contribute to improved gut health, reduced allergies and lactose intolerance, enhanced immune function, and a richer, more natural taste. However, alternative health advocate Ray Peat has noted in interviews that modern “quick flash” pasteurization results in minimal vitamin loss, showing that some nutritional differences are smaller than often assumed [29].

Critics of strict government regulation view the crackdown on raw milk as an infringement on food rights and personal autonomy. They argue that pasteurization mandates often reflect bureaucratic overreach and a precautionary mindset that ignores the nuances of small-scale, responsible raw milk production.

Underlying these debates is a broader scientific tension between competing views of health and disease. The ongoing discussion between germ theory and internal environment theory draws on the work of thinkers like French chemist Antoine Béchamp, French physiologist Claude Bernard, and Russian zoologist Élie Metchnikoff. These perspectives challenge the dominance of Louis Pasteur’s germ theory and invite a more holistic view of microbial life, which is not solely as a threat, but as a necessary and dynamic part of human health.

What the science says

For thousands of years, raw milk from healthy, pasture-fed cows on small farms and in households was consumed safely under hygienic conditions. Early milkborne disease outbreaks are often attributed to urbanization and industrial-scale dairies, which sometimes involved poor animal welfare and improper feeding or milking practices. Pasteurization emerged as a response to these hygiene and safety challenges, addressing large-scale outbreaks rather than serving as an inherent condemnation of raw milk itself.

Milk contains a mix of healthy fats, along with important vitamins and minerals. Some studies suggest that butyric acid, a type of fat found in milk, may help regulate how our genes work and could even play a role in cancer prevention by isolating, especially in inducing death by apoptosis in colon cancer cells [30]. Caprylic and capric acids may have antiviral effects, and caprylic acid has even been linked to slowing tumor growth in some research [31] [32]. Lauric acid is known for its antiviral and antibacterial properties and might help prevent tooth decay and plaque buildup [33]. Milk fat also helps the body absorb fat-soluble vitamins like vitamin A, making it an important part of a balanced diet.

Pasteurization slightly changes some of the whey proteins in milk, but it doesn’t reduce the overall nutritional quality or how well our bodies can absorb those proteins. There’s a small loss of an important amino acid called lysine during heating, but other amino acids remain mostly unaffected [34].

The size of fat droplets in milk also affects how well our bodies can break them down. Smaller fat droplets are easier to digest because they have more surface area for enzymes to work on [34]. This is where homogenization comes in, it breaks down the fat globules into smaller sizes, which is believed to help improve how the body absorbs milk fat.

The impact of heat treatments like pasteurization or UHT on the nutritional value of milk is quite minimal. Studies show that important water-soluble vitamins, such as B2 (riboflavin), B5, and niacin, as well as fat-soluble vitamins A, D, and E, are mostly preserved, even during standard sterilization [34] [35]. While other nutrients, such as vitamin B1, vitamin C, and folate, have shown a significant decrease after pasteurization, the impact on nutritional value is usually minimal since milk is not considered a primary source of these nutrients [35]. The extent of loss is influenced by the temperature and duration of the heating process, with high-temperature methods (e.g. UHT and in-bottle sterilization) causing greater reductions, though standard pasteurization results in relatively small losses, for instance, vitamin B1 content might decrease by up to 40% in the less common in-bottle sterilized milk [36]. And in some cases, milk is fortified to make up for any small losses.

As for minerals like calcium, magnesium, phosphorus, and zinc, they remain stable during pasteurization and homogenization, with no significant changes in their levels or how well our bodies can absorb them [34] [37].

Credit: Raw or heated cow milk consumption: Review of risks and benefits

Raw milk contains various enzymes and antimicrobial systems that help inhibit the growth of microorganisms and contribute to immune protection, particularly for young calves [34]. These include enzymes and proteins with natural antimicrobial properties. However, many of these systems are inactivated by pasteurization due to the high temperatures involved. While this heat treatment enhances microbial safety, it also eliminates the activity of beneficial enzymes and proteins that may support immune function.

Credit: Raw or heated cow milk consumption: Review of risks and benefits

Despite their presence, milk enzymes play a minimal role in human digestion, as most are broken down in the stomach by pepsin or destroyed by acidic gastric pH [37]. Additionally, even in raw milk, enzyme activity is limited at standard refrigeration temperatures used for storage [38]. The concentration and effectiveness of these enzymes are highest in colostrum (the first milk produced after birth) but decline rapidly during lactation, reaching levels considered to have little practical relevance for adult human consumption of raw milk [34].

Raw milk is often promoted for its potential immune-boosting benefits, especially its ability to support gut health by enriching the gut microbiota. It can contain probiotic bacteria, which are believed to contribute to a healthier digestive system. However, the actual health impact of these probiotics appears to be limited. Research indicates that in order to produce a meaningful physiological effect, the number of viable probiotic organisms consumed must be 1,000 to 10,000 times higher than the typical levels found in raw milk [34]. Additionally, many of the bacterial strains present in raw milk have difficulty surviving the harsh environment of the digestive tract, and their growth is further hindered by the low temperatures needed to safely store raw milk [34].

Some have suggested that raw milk may be better tolerated by individuals with lactose intolerance or milk allergies. However, the science is nuanced. The primary allergenic protein in milk is β-lactoglobulin [34]. Reducing the risk of milk allergy often involves modifying this protein, either by removing it or lowering its molecular mass. However, the effectiveness of this process varies depending on both the protein structure and individual sensitivity [34].

Lactose intolerance, by contrast, is caused by a deficiency in lactase, the enzyme needed to digest lactose. Importantly, both raw and pasteurized milk contain similar levels of lactose, and neither contains lactase [34] [37]. Therefore, people with lactose intolerance generally do not tolerate either form of milk well. Some studies suggest, however, that lactobacilli can produce lactase in the intestine. This may help explain why certain lactose-intolerant individuals report better tolerance of raw milk. One study observed a significant increase in Lactobacillus abundance in the gut microbiome of raw milk consumers over a twelve-week period [39]. Still, fermented dairy products such as yogurt and aged cheeses are often better tolerated, as the fermentation process hydrolyzes lactose, making it easier to digest [34] [37].

Several studies suggest that raw milk consumption may be associated with improved outcomes in certain conditions, such as diabetes, arthritis, and allergies. Epidemiological research indicates that early-life exposure to raw cow’s milk may reduce the risk of developing asthma, allergic rhinitis, hay fever, pollen allergies, and atopic sensitization [34] [40] [41]. These protective effects are thought to be due to components in raw milk that are sensitive to heat, such as whey proteins, immunoglobulins, and lactoferrin, as well as a higher fat content, which are diminished or destroyed by pasteurization [34] [37]. However, some evidence suggests that the observed immune benefits may be more closely linked to general farm exposure or contact with animals, rather than raw milk consumption specifically [42].

Another hypothesis proposes that regular consumption of raw milk may enhance immune resilience through cross-immunity, developed by repeated exposure to non-virulent strains of pathogens. While interesting, this theory remains speculative and is not currently supported by robust scientific data.

In the case of diabetes, research is still limited. Some studies have explored the possible role of A1 beta-casein (a protein variant found in some cow's milk), and its derivative compound, beta-casomorphin-7, which may form during milk storage or processing [43] [44]. These compounds have been suggested as potential dietary triggers for conditions such as type 1 diabetes, autism, and cardiovascular disease, although conclusive evidence remains lacking [45] [46].

As for arthritis and other inflammatory joint diseases, there is currently no strong clinical or epidemiological evidence that raw milk offers unique protective or therapeutic benefits. In fact, in genetically susceptible individuals, exposure to pathogens such as Mycobacterium avium subspecies paratuberculosis (MAP), occasionally found in raw milk, may potentially contribute to the development or triggering of arthritis [47].

Raw milk offers a distinctly different mouthfeel and taste compared to pasteurized milk, largely due to the absence of processing methods like pasteurization and homogenization. It retains its natural cream content, giving it a richer, creamier texture that many people find appealing and even consider superior in taste. The presence of intact flavour compounds may contribute to a more complex and nuanced taste profile. Additionally, factors such as the animal’s diet, environment, and overall feeding practices can influence the flavour of raw milk, often making it noticeably different from large-scale commercial pasteurized milk. Taste perception is also shaped by psychological factors, including cultural practices, food beliefs, and even nostalgia, which can enhance the appeal of raw milk for some consumers.

Debates over germ theory play a significant role in shaping the philosophy behind today’s raw milk movement. Antoine Béchamp proposed the "microzymian theory," suggesting that disease results from imbalances within the body's microzymas (tiny natural organisms) rather than external germs invading the body. In his view, microbes were a symptom of disease, not its cause. This perspective challenges Pasteur’s germ theory and underpins skepticism about artificially killing bacteria in raw milk, emphasizing instead the importance of maintaining internal health and balance.

Claude Bernard, another influential figure, emphasized the importance of the milieu intérieur (the body’s internal environment) and the need for systemic balance to maintain health. His perspective aligned with critics of pasteurization, who believed that heat treatment disrupted the natural integrity and nutritional value of milk.

Élie Metchnikoff introduced the concept of phagocytosis and cellular immunity and emphasized the role of beneficial microbes in supporting health. He advocated for the consumption of probiotics and fermented foods, a view embraced by raw milk proponents who argue that pasteurization destroys the “good” bacteria that support human health.

Who it might help and/or harm?

There’s no guide to follow, but people at high risk of complications from consuming raw milk, such as pregnant women, the elderly, and children, should be aware of the risks before consuming it.

Common questions

Is raw milk safe to drink?

Rather than making a blanket statement of “safe” or “unsafe,” here are a few important facts to consider:

• Pathogens: Raw milk can carry harmful microbes, including E. coli O157:H7, Listeria, Salmonella, Hepatitis A, and even H5N1. However, pasteurized milk is not entirely risk-free either.
• Epidemiology: From 2005 to 2020 in the United States, leafy greens, fruits, peanut butter, and oysters were linked to far more deaths, illnesses, and hospitalizations than raw milk.
• Nutrition: The nutritional differences between raw and pasteurized milk are minimal. Scientific evidence shows no significant loss of most nutrients after pasteurization or UHT treatment.
• Enzymes and probiotics: While certain enzymes and antimicrobial systems in raw milk are deactivated by pasteurization, their activity at standard refrigeration temperatures is already limited. Moreover, studies suggest that to produce a meaningful physiological effect, the number of viable probiotic organisms consumed would need to be thousands of times higher than the levels typically found in raw milk, and most of these organisms do not survive the harsh environment of the digestive tract.

So, is raw milk safe? The answer isn’t black and white. While its nutrition is similar to pasteurized milk, the risk of harmful bacteria is real, which is why safety remains the key issue.

Does raw milk taste better?

Many people say raw milk tastes better because it is creamier, richer, and has a more complex flavor than pasteurized milk, which comes from its natural cream content. The taste can also vary depending on the animal’s diet and environment, which makes it different from mass-produced milk. However, whether it tastes better is subjective and often influenced by personal preference, culture, and even nostalgia.

I’m lactose intolerant, but I can drink raw milk without issues. Why is that?

Lactose intolerance is caused by a deficiency of lactase, the enzyme required to digest lactose. Both raw and pasteurized milk contain similar amounts of lactose, and neither provides lactase, which is why people with lactose intolerance generally struggle with both forms.

However, some individuals with lactose intolerance report being able to consume raw milk without discomfort. One possible explanation is the presence of lactobacilli in raw milk, which may produce lactase in the intestine and assist with lactose digestion. Scientific studies have also reported a significant increase in Lactobacillus abundance in the gut microbiome of raw milk consumers over a twelve-week period.

This article is for informational purposes only and does not constitute medical advice. Consult a healthcare provider before making changes to your health routine.