The truth about raw milk

by Ryan Nebeker

Published: 1/24/25, Last updated: 1/24/25

Raw milk is regarded as a high-risk food by microbiologists and food safety experts. Yet interest in raw milk products — and their wide array of purported health benefits — seems to be growing, with sales rising substantially since 2020. For some, it’s about taste, but for many, consuming raw milk scratches an antiestablishment itch. Whether it’s about ignoring government safety warnings and reclaiming health freedom or divesting from the industrial food system, raw milk has become a countercultural elixir for people across the political spectrum. At the same time, pasteurized milk is often stigmatized in holistic health spaces as processed and therefore unhealthy.

Read our full report The FoodPrint of Dairy

With Robert F. Kennedy Jr., a holistic health advocate and raw milk lover, now in charge of the Department of Health and Human Services, it’s possible that federal guidelines around raw milk production and consumption could change. This has brought conversations about what used to be a niche product to national attention, making claims about raw milk’s alleged risks and benefits worth investigating.

“Regular” vs. raw: What’s the difference?

Raw milk refers to milk that hasn’t been pasteurized, a heat-treatment process that eliminates potentially harmful microorganisms and reduces the risk of early spoilage. There are several different methods of pasteurization, with High Temperature Short Time (HTST) being the most common in the U.S. During HTST pasteurization, milk is very quickly and precisely heated to 161 F for 15 seconds before being rapidly cooled. This process doesn’t necessarily kill all microorganisms in milk, but it reliably kills those that can cause illness in people as well as dramatically reducing the quantity of bacteria that can cause spoilage.

Milk can also be ultrapasteurized to extend its shelf life by heating it to 280 F for two seconds. This process is more commonly used for organic milk and other products that might sit in a refrigerator for a longer time before being sold. Ultra High Temperature (UHT) pasteurization combines a high heat method with sterile packaging to create milk that remains shelf stable at room temperature for months; it is the most common processing method in many other countries. These higher temperature methods often leave milk with a slightly “cooked” taste. It’s worth noting that, despite the name, ultrapasteurized and UHT milks aren’t ultraprocessed foods, or subject to any more processing or alteration than normal pasteurized milk.

Terms to Know
Pasteurization
A heat-treatment process that eliminates potentially harmful microorganisms and reduces the risk of early spoilage.

Pasteurized milk is also typically homogenized, a process that subjects the milk to high pressure, thereby breaking up its fat globules and evenly distributing them throughout the liquid. This ensures that tiny droplets of fat remain suspended in the milk rather than rising to the top, giving homogenized milk a more uniform mouthfeel and making it more nutritionally consistent glass to glass. By contrast, raw milk is always unhomogenized: Its fat rises to the surface, yielding a drink that’s rich at the top and closer to the texture and taste of skimmed milk at the bottom. It isn’t just raw milk that’s sold unhomogenized, however. Pasteurized, unhomogenized milk is frequently available at farmers’ markets and some grocery stores, where it is often sold as creamline milk.

Terms to Know
Homogenization
A process that subjects the milk to high pressure, thereby breaking up its fat globules and evenly distributing them throughout the liquid.

Whether it comes from a small family farm or a megadairy, almost all milk sold legally in the U.S. today is pasteurized, thanks to state laws that limit the sale of raw milk. There’s also a federal law barring the interstate trade of raw milk that’s forced the industry to remain relatively small. However, laws about raw milk are loosening around the country, with most states having some legal avenue to purchase raw milk, whether through retail stores or directly from farmers. In states where laws still prohibit raw milk from being sold for human consumption, farmers sometimes circumvent this by marketing raw milk as pet food.

What are the risks of consuming raw milk?

Raw milk naturally contains a diverse community of bacteria, most of which are neither harmful nor beneficial to human health. However, raw milk can also carry bacteria that cause serious illness and death.

Historically, raw milk was one of the most frequent causes of foodborne illness, with bacteria like Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella and Salmonella causing diseases like brucellosis, salmonellosis, streptococcal infections, diphtheria and “summer diarrhea.” Both human and bovine tuberculosis infections were also commonly acquired from raw milk. These infections, along with low rates of sanitary breastfeeding practices, contributed to infant mortality rates more than 30 times higher than those of today.

96%

of dairy-derived illnesses are caused by unpasteurized dairy products.

Since the adoption of widespread pasteurization, however, milk has become a relatively low-risk food, with most incidents of foodborne illness in milk stemming from an incomplete pasteurization process or contamination after pasteurization. On the other hand, unpasteurized dairy products are responsible for 96 percent of dairy-derived illnesses, despite being consumed by just 3-4 percent of the U.S. population. Between 1998 and 2018, raw milk outbreaks in the U.S. sickened more than 2,600 people, leading to 228 hospitalizations and three deaths. These totals may be an undercount, given that some people are sickened by raw milk outside of known large outbreaks.

While modern medicine has made recovery from many foodborne illnesses easier, many of these bacteria can still cause serious illness, long-term organ damage (especially to the kidneys) and death. This risk is especially elevated for young children, the elderly and anyone with a compromised immune system.

Bird flu: a new risk

While bacteria are behind most of the foodborne illnesses in milk, viruses are also a concern. And as avian influenza, also known as H5N1 or bird flu, infects herds of dairy cows, public health experts are sounding the alarm that raw milk might present a serious risk for human transmission. Scientists have determined that influenza viruses, including bird flu, can remain infectious in raw milk for at least five days; pasteurization, on the other hand, inactivates the virus.

Meanwhile, researchers have found that milk and milking equipment is the most common way that bird flu is transmitted between cows. Close contact with cows and milking equipment has also sickened dozens of dairy workers. There haven’t been any confirmed human cases of bird flu stemming directly from raw-milk consumption, and advocates of raw milk have been quick to deny that it even contains the virus. But scientists have confirmed bird flu as the cause of death for several cats that consumed raw milk, including some that had no other exposure to birds or cattle, proving that milk can both carry the virus and sicken animals that aren’t cows. For public health experts, this indicates that the possibility of human transmission is high enough to warrant avoiding raw milk. And contrary to claims by the raw milk producer whose milk was implicated in the cats’ deaths, there’s no evidence that consuming raw milk from infected cows would confer any kind of immunity or protection from bird flu.

So far, USDA monitoring data suggests that bird flu is widely present in milk, including raw milk sold for human consumption in California. And although that milk was recalled, raw milk sold across the country could still carry the virus as long as bird-flu outbreaks in dairy cows remain poorly monitored.

Why are people passionate about raw milk?

While some people choose to drink raw milk because they prefer the taste or they want to support local producers, raw milk also has a devoted following among people who believe it’s a “superfood” that’s helped them restore their bodies and build a resilient immune system. Many pro-raw milk interest groups have published consumer testimonials stating that raw milk was an integral part of their healing from a number of conditions, ranging from gastrointestinal issues and allergies to serious autoimmune diseases. But how do these claims about raw milk’s benefits stack up against scientific studies?

Is raw milk more nutritious?

Any level of food processing has the potential to either change the nutrient composition of a food or alter how easily our bodies can absorb those nutrients. Raw milk advocates claim that pasteurization amounts to killing a living food, draining it of nutrients and destroying its health-promoting compounds.

But pasteurization is a relatively gentle heating compared to more intense processes like boiling (which many farm families do with raw milk from their own cows), so it does relatively little to the nutrient content of milk. Minerals tend to be heat stable, so the overall concentration of nutrients like calcium and phosphorus are essentially unaffected. And despite what raw milk advocates claim (often by misrepresenting research about the effects of boiling or overheating milk), the gentle heating of pasteurization doesn’t change the bioavailability of those minerals, either. This means that the human body can absorb these nutrients just as freely from pasteurized milk as it can from raw milk.

Heating milk does have some impacts on vitamin levels, however. One meta-analysis of several studies showed that pasteurization can slightly reduce levels of vitamins B1, B2, B12, C and folate. That said, only Vitamins B2 and B12 are present in milk in nutritionally significant amounts to begin with. Even after pasteurization, milk is still an excellent source of both Vitamins B2 and B12, with one glass providing 34 percent and 48 percent of the recommended daily intake, respectively. Furthermore, the same analysis found that concentrations of Vitamin A actually increased with heat treatment.

The overall quantity of macronutrients — carbohydrates, proteins and fats — is also left unchanged by pasteurization, though the shape of some proteins does change with heating in a process called denaturing. This doesn’t impact the nutritional quality of the protein in milk, however.

Some of the proteins that get denatured during pasteurization are enzymes, compounds that help facilitate certain chemical reactions. Some enzymes in raw milk help break down fat and protein, while others act as antimicrobial agents. These functions — and their alleged loss after pasteurization — are the basis of many health claims about raw milk.

Raw milk advocates say these enzymes make it easier to digest than pasteurized, and that it’s safe to be enjoyed even by people with lactose intolerance and some dairy allergies. But contrary to widely circulated claims, raw milk does not naturally contain lactase (an enzyme that breaks down lactose), which is produced either in the human gut or by lactic acid bacteria as they ferment milk into cheese or yogurt. Nor are these lactic acid bacteria present in fresh, raw milk in quantities that would allow them to make a relevant quantity of lactase. Ultimately, there’s little more than anecdotal data to support the idea that raw milk helps people overcome lactose intolerance: A study of people with confirmed lactose intolerance found that they were no better at digesting raw milk than they were pasteurized milk. Meanwhile, the other enzymes in raw milk — proteases and lipases — that are alleged to aid in milk digestion don’t seem to play much of a role either, given they’re mostly inactive when refrigerated and quickly denatured by the acidic environment of the human stomach.

When it comes to antimicrobial benefits, the enzymes in raw milk do exhibit some properties that help protect milk against early spoilage. But the lower-temperature pasteurization methods that are standard in the U.S. don’t actually disable most of these enzymes; in fact, they leave most enzymes at least 70 percent effective. And while UHT pasteurization — the high-heat process used for those shelf-stable rectangular cartons — does disable many of the enzymes, the combination of higher temps and sterile containers eliminates the need for spoilage-inhibiting enzymes in the first place. It’s also worth noting that the overall quantity of these enzymes in raw milk is typically low enough that they make a minimal impact on digestion. What’s more, if some of these enzymes are present in significant quantities, that can be an indication that the cow is dealing with mastitis or another infection that could render the milk unsafe.

Is raw milk a probiotic?

Another pillar of raw milk’s alleged superfood status is the idea that it acts as a probiotic, a food that confers live microorganisms that benefit the gut or other systems in the body. Raw milk does contain a wider variety of bacteria than pasteurized milk, including a few strains that play a role in fermenting milk (which yields easy-to-digest probiotic foods like kefir and yogurt); technically speaking, these bacteria could have some benefit to human gut health when they’re consumed in adequate quantities. But that stipulation about quantity is an important stumbling block: In order for a food to act as a probiotic, it must have an appropriate dose of microbes, often between hundreds of millions to hundreds of billions of actively reproducing beneficial bacteria. Raw milk, especially when produced under hygiene stipulations designed to minimize bacterial load, simply doesn’t have enough. Fermentation of the milk can increase the number of beneficial microbes, but it also leaves an opportunity for pathogens to proliferate. And unfortunately, unlike probiotics, many of the pathogenic bacteria that can show up in raw milk are capable of causing illness even when they’re present in small amounts.

Thankfully, there are other sources of beneficial bacteria beyond raw milk and fermented raw milk products. Lactobacillus, for example, is added back to pasteurized milk products to make yogurt, sour cream, kefir, creme fraiche and more, and these ultimately provide far more of the beneficial bacteria than raw milk does — without the added risk of pathogens.

Allergies and the immune system

Allergies are one arena where raw milk consumption may show some health benefit, though the research into this phenomenon has some issues. Scientists have long observed that children who grow up on farms develop fewer serious allergies than those who grow up mostly indoors or in urban environments. Several early studies have tried to pinpoint the causes of this “farm kid effect,” with a few considering raw milk consumption as one of the variables. Among other findings, these studies found associations between raw milk consumption and lower rates of allergies, respiratory infections and eczema.

Ultimately, however, it’s hard for researchers to untangle where raw milk consumption sits in the web of environmental factors that children on farms experience. Other features of the farm environment — like early and frequent exposure to dust, pollen, soil and more — also seem to play a protective role against allergies. Notably, some of the research on farm kids and milk doesn’t even technically focus on raw milk: Without access to high-quality modern pasteurization equipment, farm families often consume boiled milk, which has dramatically different qualities than its pasteurized or raw counterparts. Without better controls indicating whether kids were consuming raw milk or boiled, it’s hard to dial in on its effects.

Critically, these farm-kid health studies are entirely observational, and while researchers might get clearer answers by designing experiments where children are given raw milk in a more controlled environment, this hasn’t happened. Scientists in one review highlighted a telling reason why: It would be very difficult to get review board approval for a study where children are intentionally fed raw milk, given the high risks associated with consuming it.

This is ultimately the difficult contradiction facing raw milk. The available evidence suggests the potential protective effects against allergies, respiratory issues and eczema are strongest for infants who consumed raw milk in their first year of life, but infants and children are also far more vulnerable to illnesses caused by pathogens in raw milk. In outbreak after outbreak, children are the most hospitalized and most likely to become seriously ill. Even outside of well-documented outbreaks, children are the most likely people to acquire infections from raw milk, with one analysis of ten years of Minnesota health data finding that 25 percent of people with serious illnesses from raw milk were children, despite the milk being consumed by a wide age group.

On the other hand, some research has shown pasteurization can actually reduce the potential for milk to cause certain kinds of allergies.

Is it possible for raw milk to be produced safely?

Advocates for raw milk sometimes point out that, from a numbers perspective, raw milk isn’t a leading cause of foodborne illness, and that other foods without its complicated reputation — especially salad greens — are responsible for far more outbreaks. While this can be attributed mostly to the fact that raw milk consumption is still very low, it also obscures the reality that many foodborne illnesses in fresh produce actually originate from cows. Manure-contaminated irrigation water or bacteria-laden dust from animal agriculture facilities are common sources of E. coli and other pathogens, underscoring the risk of eating raw food that’s been in close proximity to animals.

But if the high concentration and wide spread of these bacteria might stem from the scale of industrial animal agriculture and its disregard for the surrounding environment, does that mean that pathogens can be eliminated with better management? Raw-milk producers often present their farms as the polar opposite to the modern megadairy, where, as the Raw Milk Institute puts it, milk is “produced with little care towards preventing contamination” because it’s going to be pasteurized later. They contrast this with farms where raw milk is produced with the intention of being consumed raw — a place where happy, clean cows are carefully milked by hand in a way that eliminates the potential for contamination.

It’s an appealing narrative, and eliminating potential sources of contamination is an important part of any food-safety plan. The Raw Milk Institute and others offer a series of steps that producers can undertake to reduce the risk of pathogenic bacteria ending up in milk, including careful monitoring of cows for symptoms of infection and periodic sampling of milk to ensure low counts of bacteria.

In reality, however, this doesn’t guarantee safety. Even if good management can lower the total amount of bacteria in raw milk, it doesn’t eliminate risk —  some pathogens can be transmitted from environments that seem clean, or from cows that appear healthy.

And given the diversity of bacteria present in raw milk and the potential for many different kinds of bacteria and viruses to be pathogenic, periodic testing isn’t foolproof either. It’s simply not possible to accurately screen milk for every pathogen of concern. Depending on the method, testing can also miss pathogens because they may not be uniformly distributed throughout the milk, or because they’re present at undetectable levels that can increase during storage.

Ultimately, the available controls can only do so much — they cannot guarantee complete protection. Scientists are researching alternative pathogen-eliminating technologies that don’t involve heat treatments, but for the time being, pasteurization or boiling are still the only ways to effectively eliminate all pathogens of concern. Without that foolproof kill step, raw milk is still a high-risk food, especially for infants, the elderly and anyone with a compromised immune system.

Top photo by Romo Lomo/Adobe Stock.

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