Raw milk is not safe to drink and doesn't offer unique health benefits
Rejecting scientific technologies like pasteurization has real [negative] consequences
Honestly, can’t believe I need to say this in 2024 in the midst of an H5N1 outbreak that is being spread in part by dairy cattle, but - unpasteurized milk is not safe to drink. And yet, we are seeing a increased interest in raw milk, which is putting individual and public health at risk.
Increased interest in drinking raw milk is being driven by unqualified wellness “influencers” - not scientific experts.
Raw milk sales are up since the announcement of H5N1 avian influenza virus in dairy cattle: approximately a 25% increase in raw milk purchases versus the same period last year. While most milk sold is pasteurized, this trend is disturbing for many reasons.
The legality of selling raw milk varies state by state, but the risks remain no matter where you are. Unfortunately, influencers on all ideological sides are touting completely unsubstantiated claims about raw milk which is driving this increased demand for this risky food product.
Can we please stop confusing notoriety with expertise?
I cannot tell you how frustrating it is to have your entire life’s work be discarded in favor of some prominent celebrity or social media personality, simply because they have a lot of followers. So, just to emphasize things: Gwyneth Paltrow and RFK Jr. have ZERO business speaking on these topics. Both of these individuals have a long history of undermining actual science and medicine and promote harmful wellness trends that make them a lot of money.
Raw milk contains many pathogens that can cause serious illness.
Raw milk products are products that have not been pasteurized.
Raw milk products are not safe to consume, now or ever. In fact, raw milk is considered one of the riskiest foods to consume by all credible scientific and food safety agencies.
Raw milk can contain viruses and bacteria from the animals (cows and goats) and the environment in which they are housed. Most commonly, consumption of raw milk is associated with infections and illnesses from:
Escherichia coli.
Campylobacter jejuni.
Salmonella
Listeria monocytogenes.
Brucella abortus.
Symptoms of foodborne illness from these pathogens include diarrhea, stomach cramping, and vomiting. However, they can lead to even more serious complications.
Campylobacter infections, which cause 1.5 million bacterial-associated diarrheal illnesses in the US every year, are also the most common cause of Guillain-Barré syndrome (GBS).
Guillain-Barré syndrome is a condition where the immune response affects the nerves. Symptoms can range from mild to severe, typically beginning with tingling and weakness in the extremities, but can progress to muscle weakness, difficulty walking, facial paralysis, difficulty swallowing and chewing, pain, and coordination issues. GBS can also impact bladder and bowel control. In severe cases, respiratory failure or complete paralysis can occur. While most people do fully recover, this can take weeks to years, and some people do experience lasting complications like blood clots, residual weakness, chronic pain, etc.
You might remember hearing about GBS by people discouraging vaccinations, citing it as an adverse event. But the reality is INFECTIONS are far more likely to cause Guillain-Barré than a vaccine.
Roughly 1 in every 1,000 people with Campylobacter infection develop Guillain-Barré. So every year, about 1,500 people will develop Guillain-Barré solely from Campylobacter. What’s more? Many Campylobacter infections go unreported, and if rates of raw milk consumption increase, these numbers may also increase.
E. coli infections can cause hemolytic uremic syndrome which can be fatal.
Certain strains of Escherichia coli are considered Shiga toxin-producing E. coli (STEC). These strains, which include O157, O26, O45, O103, O111, O121, and O145 have a virulence factor where they’ve acquired the gene to produce a protein toxin that was evolutionarily acquired from Shigella dysenteriae, the bacteria that causes dystentery.
These toxins, Stx1 and Stx2, interfere with essential cellular functions in our bodies, causing cell death and tissue destruction. This can cause complications such as hemorrhagic colitis and gastroenteritis, characterized by severe abdominal cramps, vomiting, and bloody or non-bloody diarrhea. More seriously, STEC and the toxins products can cause thrombotic thrombocytopenic purpura (TTP) or hemolytic uremic syndrome (HUC).
Hemolytic Uremic Syndrome causes hemolytic anemia (rupture and death of red blood cells), thrombocytopenia (destruction of platelets), and acute kidney injury. Together, these can cause kidney failure, multi-organ failure, hemorrhage, and death.
Thrombotic Thrombocytopenic Purpura (TTP) leads to the formation of small blood clots in blood vessels (thrombi), thrombocytopenia (destruction of platelets), red blood cell destruction (hemolytic anemia), neurological damage, and organ failure.
Both HUS and TTP as a result of E. coli infections can cause paralysis, organ failure, stroke, and death. More than that, antibiotics to clear the infection are ineffective, because killing the bacteria releases more toxin, which actually exacerbates the illness.
Why would you risk these things through consuming raw milk?
In addition, raw milk can contain a variety of viruses that can be found in cows, some of which, like influenza viruses, can be transmitted to humans. Those at greatest risk for serious, potentially fatal illnesses from these pathogens are young children, older adults, and those with compromised immune systems.
The consumption of raw milk and raw milk products is discouraged by all credible scientific and regulatory agencies. Why would you put your family at risk for absolutely no reason?
Guess what? Pasteurization drastically reduces the risk of ALL of these illnesses.
The improved safety of milk products is due to pasteurization. Before the Pasteurized Milk Ordinance was implemented in 1924, foodborne illness linked to dairy consumption was substantial. In 1938, milkborne outbreaks constituted twenty-five percent (25%) of all food- and water-borne disease outbreaks. Today, dairy products account for fewer than 1% of these illnesses.
And yet, we are seeing food poisoning cases in dairy products creep up again, solely due to the consumption of raw milk products. Raw milk products have been the cause of over 200 food-borne disease outbreaks in the US in last 20 years. These rates are increasing as certain states relax laws that previously prohibited the sale or distribution of raw milk products.
78% of single state raw milk outbreaks occurred in states where the sale of unpasteurized milk was permitted. The majority of illnesses and hospitalizations as a result of consumption of raw milk are in children.
While pasteurization was adopted commercially for milk products in 1882, and the first law requiring pasteurization was passed in Chicago in 1908, there are variations in law state by state.
Currently, 29 states allow the sale of raw milk, and in nearly every state, people can find ways to acquire raw milk through milk sharing, direct under the table purchase, and sale via “pet food” regulations.
Pasteurization is one of the greatest microbiological technologies that improved public health.
Pasteurization was invented by French microbiologist Louis Pasteur in 1862, and involves heating a food product in order to kill or render inactive potential microorganisms so they cannot replicate and cause food-borne illness.
In the US, the primary method used to pasteurize milk is called High Temperature Short Time (HTST) pasteurization. Milk is rapidly heated to a specific temperature (usually around 161°F or 71.7°C) for a short period (usually 15 seconds), then rapidly cooled. This kills potentially harmful bacteria such as E. coli, Salmonella, and Listeria, as well as inactivates viruses such as influenza viruses, herpesviruses, parvoviruses, and others that may be found in dairy milk.
This rapid heating and cooling also preserves the taste of milk while limiting protein denaturation, which also preserves the nutrition of milk.
Pasteurized milk is safe to drink.
On top of the other previously stated risks, we are currently experience an outbreak of H5N1 avian flu, that is spreading in part through dairy cattle. In fact, I spoke with AGDAILY earlier this month about this very topic:
Pasteurization inactivates H5N1 viruses. Milk that is not pasteurized can contain active H5N1 virus.
The FDA and news outlets reported that H5N1 had been detected in commercially available pasteurized milk samples, leading to a frenzy of fear among people who drink dairy products. This detection was based on the previously described PCR-based testing, which cannot differentiate between viral fragments and live virus.
Note: pasteurization is very effective at inactivating potentially harmful microorganisms, including influenza viruses. That’s why we’ve been pasteurizing food products for over 100 years.
The National Institute for Allergy and Infectious Diseases confirmed that pasteurized milk samples do not contain active influenza virus.
But this doesn’t apply to raw milk.
H5N1 virus remains infectious in raw milk for hours.
A new study in Emerging Infectious Diseases (currently in early release version) demonstrates that yes, indeed, H5N1 virus persists in unpasteurized milk and remains infectious in raw milk and on milking unit surfaces for several hours.
This study was conducted in part to advise on farm worker safety measures, but it has obvious implications for those who opt to consume raw milk. If you recall from my previous newsletter, the likelihood of infection of flu viruses through ingestion is rare, there are potential routes of exposure (like inadvertent inhalation or aspiration) around raw milk products that aren’t worth the risk, in addition to the other risks of raw milk.
The raw milk fanaticism as a result of the H5N1 outbreak coverage appears to be motivated in part by people who want to prove they “know more” than the experts and also, people who are trying to gain immunity to H5N1. Neither of these things are a good idea.
Drinking raw milk isn’t giving people immunity to H5N1
You’ve probably heard a lot about passive immunity in the context of breast milk, and how a nursing mother can provide some temporary protection to their infant related to an array of illnesses that put a newborn at risk (like RSV, COVID-19, influenza). That’s where the logic plays in here. People think that the same may be true in drinking cow’s milk of a cow that developed an immune response to H5N1.
Unfortunately, this passive immunity is only temporary. This is not going to lead you to actively develop immunity to H5N1. Ingesting cow’s milk - whether raw or pasteurized - will mean you ingest that cow’s antibodies, but most of those antibodies will be digested and degraded once they hit the acid in your stomach (the same phenomenon I discussed re the myth about GMOs changing your DNA).
Yes, raw milk could contain live H5N1 virus. But as I discussed in this piece, H5N1, like all flu viruses, is a respiratory virus, not a gastrointestinal virus. Unlike GI viruses (like norovirus), H5N1 doesn’t have evolutionary methods to survive the GI tract. Additionally, the receptors H5N1 bind to in order to infect us are primarily in the respiratory tract. So if you did ingest H5N1 via raw milk, it is unlikely that you would develop a robust enough immune response through ingesting the virus to lead to protection against exposure in the future.
Drinking raw milk isn’t nutritionally superior
Pasteurization is often cited by unqualified individuals as a process that “deteriorates” the quality of milk. While heating substances can cause some protein denaturation (the name for a process where we disrupt the tertiary structure of a protein), it doesn’t change the amino acid composition or linkages of those proteins.
A note: denaturation typically inactivates enzymes: proteins that act upon other molecules, usually to cut them or fuse them. But these enzymes aren’t something that the human body needs, so deactivating them does not impact your health.
More importantly, pasteurization doesn’t impact how YOU process and extract the nutrients from these milk proteins.
Milk primarily contains casein and whey proteins. Casein is very stable and is not impacted by pasteurization. Whey proteins, primarily beta-lactoglobulin, alpha-lactalbumin, immunoglobulins, and serum albumin, can experience partial denaturation, but nutritional content and value of milk proteins remain intact. Amino acids and protein content are preserved, and in some instances, pasteurization can actually improve the digestibility of certain whey proteins.
What about other nutrients, like vitamins? A systematic review and meta-analysis inclusive of 40 different studies concluded that minor losses there was a statistically significant decrease only in vitamin B1, but this is not clinically relevant because our major dietary sources of vitamin B1 (also called thiamin) are through grains, meats, and fish.
Drinking raw milk isn’t substantively reducing allergies or asthma
This claim originates as a result of the “farm effect" - an association between children growing up on farms and reduced prevalence of allergies. Only limited data exist to suggest a weak association between this, and this is not causally or uniquely related to consuming raw milk.
Development of allergies is a complex process (one I actually taught a course on last night for the New York State Department of Health!), and it is impacted by multiple factors. While there may be a relationship between early immune system education and reduced likelihood of hypersensitivity reactions like allergies, there is a complex interplay between early life immune system development, environment, genetics, and more. It is unlikely that a single “factor” is determining whether someone develops allergies or asthma, and the data related to it and raw milk are lacking.
Drinking raw milk doesn’t reduce incidence of lactose intolerance
Lactose intolerance occurs when you don’t produce sufficient quantities of lactase, the enzyme required to break down the lactose sugar into digestible subunits (see this piece for more on that). Pasteurization doesn’t reduce the levels of lactose in milk, and a very small pilot trial of 16 adults demonstrated that there was no difference in digestive symptoms after consuming raw versus pasteurized milk.
Drinking raw milk isn’t “cool” - it’s just putting your safety (and your kids’ safety) at risk.
Honestly, we need to move into an era where people aren’t listening to wholly unqualified people on social media. No, content creators on TikTok that are touting unproven benefits are not experts. No, Gwyneth Paltrow is not an expert. No, the absurd grocery story Erewhon does not determine what is healthy for you. Neither are the leaders of the “Raw Milk Institute” - in fact, Mark McAfee is a former paramedic and has no scientific, medical, or food safety credentials. All he has is a raw milk farm and an online megaphone. In fact, all of these individuals and platforms have an obvious profit motive and zero relevant qualifications. So why are they viewed as credible sources?
Just because there are loud celebrity voices who, without scientific training, claim that raw milk is superior doesn’t make it true. More than that, there are very serious risks associated with raw milk - that’s why we’ve been pasteurizing it for OVER A HUNDRED YEARS.
If you encounter anyone who is recommending drinking raw milk, please understand that they are spreading disinformation that is going to cause harm. You probably also want to be wary of any other scientific or health claims they make, since it is clear that their ability to accurately analyze scientific data is very flawed.
Thanks for joining in the fight for science!
Thank you for supporting evidence-based science communication. With outbreaks of preventable diseases, refusal of evidence-based medical interventions, propagation of pseudoscience by prominent public “personalities”, it’s needed now more than ever.
Stay skeptical,
Andrea
“ImmunoLogic” is written by Dr. Andrea Love, PhD - immunologist and microbiologist. She works full-time in life sciences biotech and has had a lifelong passion for closing the science literacy gap and combating pseudoscience and health misinformation as far back as her childhood. This newsletter and her science communication on her social media pages are born from that passion. Feel free to follow on Instagram, Threads, Twitter, and Facebook, or support the newsletter by subscribing below: