As the H5N1 avian flu virus continues to spread in poultry flocks and dairy cattle, consumers may worry about whether the U.S. milk supply is safe to drink. According to the U.S. Food and Drug Administration, the answer is yes, as long as the milk is pasteurized.
In late November, however, California regulators recalled two batches of raw, unpasteurized milk from a Fresno dairy farm after bird flu virus was detected in the milk.
No human bird flu cases associated with the milk were detected immediately following the recalls. But officials strongly urged buyers not to drink raw milk from the affected batches and to return it to the store where they bought it. They also barred the farm from distributing new batches of raw dairy products to retailers.
Despite health experts’ warning that raw milk could contain high levels of the avian flu virus, along with many other pathogens, raw milk sales are up in the U.S. Robert F. Kennedy Jr., whom President-elect Donald Trump has said he will nominate to head the Department of Health and Human Services, has asserted that raw milk “advances human health,” contrary to warnings from FDA officials and food scientists.
As an extension food scientist in a state where raw milk sales are legal, I provide technical support to help processors produce high-quality, safe dairy foods. I also like to help people understand the confusing world of pasteurization methods on their milk labels, and why experts strongly discourage consuming raw milk and products made from it.
What can make milk unsafe
Dairy products, like many foods, have inherent risks that can cause a variety of illnesses and even death. Dairy milk comes from animals that graze outdoors, live in barns and lie in mud and manure. Milk is picked up from the farm in tanker trucks and delivered to the processing plant. These environments offer numerous opportunities for contamination by pathogens that cause illness and produce organisms that make food spoil.
For example, listeria monocytogenes comes from environmental sources like soil and water. Mild infections with listeriosis cause flu-like symptoms. More serious cases are, unfortunately, too common and can cause miscarriages in pregnant women and even death in extreme cases.
Other pathogens commonly associated with dairy animals and raw milk include E. coli, which can cause severe gastrointestinal infections and may lead to kidney damage; Campylobacter, the most common cause of diarrheal illness in the U.S.; and Salmonella, which cause abdominal pain, diarrhea and other symptoms.
Keeping beverages safe with heat
In the 1860s, French microbiologist Louis Pasteur discovered that heating wine and beer killed the organisms that caused spoilage, which then was a significant problem in France.
This heating process, which became known as pasteurization, was adopted in the U.S. prior to World War II, at a time when milk was responsible for 25% of all U.S. outbreaks of foodborne illnesses. In 1973 the federal government required that all milk sold across state lines in the U.S. had to be pasteurized, and in 1987 it banned interstate sales of raw milk.
Pasteurization heats every particle of a food to a specific temperature for a continuous length of time in order to kill the most heat-resistant pathogen associated with that product. Different organisms have different responses to heat, so controlled scientific studies are required to determine what length of time at a given temperature will kill a specific organism.
Since 1924, pasteurization in the U.S. has been guided by the Grade “A” Pasteurized Milk Ordinance, a federal guidance document that is updated every two years to reflect current science and has been adopted by all 50 states. Pasteurization equipment in the U.S. must meet stringent requirements that include sanitary design, safety controls and material standards.
Pasteurization methods
Dairy processors can choose among several different types of pasteurization. When executed properly, all of these methods produce the same result: pathogen-free milk. Processors may treat milk beyond minimum times or temperatures to provide an extra margin of safety, or to reduce bacteria that can cause milk to spoil, thus increasing the product’s shelf life.
Smaller-scale processors who handle limited volumes use what are known as vat pasteurizers, also known as batch pasteurizers. Milk is pumped into a temperature-controlled tank with a stirrer, heated to a minimum of 145 degrees Fahrenheit (63 Celsius) and held there continuously for 30 minutes. Then it is cooled and pumped out of the vat.
The most common method used for commercial milk is high-temperature short-time pasteurization, which can treat large volumes of milk. Milk is pumped through a series of thin plates at high speed to reach a minimum temperature of 161 F (71 C). Then it travels through a holding tube for 15 seconds, and the temperature is checked automatically for safety and cooled.
The most complex and expensive systems are ultra-pasteurizers and ultra-high-temperature pasteurizers, which pasteurize milk in just a few seconds at temperatures above 285 F (140 C). This approach destroys many spoilage organisms, giving the milk a significantly longer shelf life than with other methods, although sometimes products made this way have more of a “cooked” flavor.
Ultra-high-temperature products are processed in a sterile environment and packaged in sterile packaging, such as lined cartons and pouches. They can be shelf-stable for up to a year before they are opened. Ultra-high-temperature packaging makes taking milk to school for lunch safe for kids every day.
Avian flu in milk
The detection of avian flu virus fragments in milk is a new challenge for the dairy industry. Scientists do not have a full picture of the risks to humans but are learning.
Research so far has shown that virus particles end up in the milk of infected cows, but that pasteurization will inactivate the virus. The FDA advises consumers not to drink raw milk because there is limited information about whether it may transmit avian flu.
The agency also is urging producers not to manufacture or sell raw milk or raw milk products, including cheese, made with milk from cows showing symptoms of illness.
Avian flu continues to appear in new species, and as of early December 2024, 57 human cases had been confirmed in the U.S. Of these, all but two were people who worked with livestock.
Two recent cases – a child in California and a teen in Canada – may indicate that young people with immature immune systems are more vulnerable than adults to the virus. With medical researchers still learning how H5N1 is transmitted, I agree with the FDA that raw milk poses risks not worth taking.
Kerry E Kaylegian is Associate Research Professor of Food Science, Penn State.
The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.
- External Link
- https://theconversation.com/avian-flu-virus-has-been-found-in-raw-milk-a-reminder-of-how-pasteurization-protects-health-245102
25 Comments
TaiwanIsNotChina
Louis Pasteur would be shaking his head at these imbeciles.
Jay
What pasteurization really does is strip milk of its natural nutrients - completely boiling away the health benefits. Raw milk, the way nature intended it, is packed with probiotics, enzymes, and vitamins that support gut health and immunity - everything pasteurized milk lacks because it's been cooked to irrelevance.
Bottom line: raw milk is real food - alive, vibrant, and untainted by industrial meddling.
Wick's pencil
But no evidence of viable virus.
Oh dear, here we go again. "Let's get everyone vaccinated!!!!"
ifd66
We only have raw milk from our goats.
As Jay says:
virusrex
Completely false, this is just an imaginary problem that has been demonstrated false.
This on the other hand are just baseless claims that have no evidence supporting them, there is no study where people drinking raw milk have in any way better health, if anything they have worse since the risk from infectious diseases is several orders of magnitude higher.
You really need to understand how industrial is the production of milk, even raw. Pasteurization is a tiny step on a long list of industrial processes that the cows and the milk is subjected.
At the titers it is being detected? definitely it is beyond credible to think all the virus are inactivated before pasteurization
https://www.nytimes.com/2024/12/05/science/bird-flu-milk-dairy-h5n1.html
It even has been observed to mediate infection in cats (and causing their death)
https://www.nytimes.com/2024/05/01/well/eat/bird-flu-milk-raw.html
At this point the claim that the virus in the milk is not viable is the one that would require evidence in order to be considered, including evidence that also explains everything else that has been congruent with milk being a significant mechanism of transmission from cows.
Imagine that, scientist prove there is an important risk and recommend a safe and effective measure that can greatly reduce that risk. Meanwhile what productive alternative do you suggest? ignoring the risk and let people die preventable deaths just because you don't like vaccines? not exactly something positive.
Wick's pencil
No, that is not proven. Your reference states: "It’s possible they were sickened by eating wild birds"
It also mentions: "There have been only two cases of avian influenza in humans reported in the United States since 2022; both people were exposed to infected animals and had mild illnesses."
Jay
Completely wrong yet again. Raw milk is unquestionably real food packed with nutrients, enzymes, and probiotics that pasteurization destroys. Studies show raw milk drinkers have fewer allergies and better gut health - something pasteurized milk scientifically cannot offer because it had been stripped of life and nutrients.
And unfortunately for you, the "risk of disease" scare tactic is simply outdated propaganda. With raw milk from healthy, pasture-raised cows, the risks are minuscule, and the benefits are enormous. Pasteurization was pushed for no other reason than to process low-quality milk cheaply and extend shelf life.
Do not ignore the bigger picture: the real danger isn’t raw milk - it’s the corporate-driven system keeping people dependent on nutrient-dead, factory-processed junk. End of story.
Wick's pencil
Any real evidence for any of that (important risk, safe, effective)?
Maybe not feeding cows grain, or at least better protecting the grain. Wild birds are attracted to the grain, and they poop on it, thus infecting the cows and cats, and contaminating the milking equipment.
virusrex
Two dozen cats that had as a common factor being feed with milk from infected cows, half of them get infected and died and the virus was of the same type and subtype than the one infecting the cows, adding an astronomically low possibility that something not observed before (outbreak of influenza A infection on cats all from avian sources) happened is not exactly a strong argument against the obvious and clear possibility that the cats were infected from the milk, it is just scientific good practice to include these theoretical possibilities in the discussion even when they are not a practical explanation.
Or as the authors of the report concluded:
In conclusion, we showed that dairy cattle are susceptible to infection with HPAI H5N1 virus and can shed virus in milk and, therefore, might potentially transmit infection to other mammals via unpasteurized milk.
And yet you are completely unable to provide those supposed studies that prove people that drink raw milk are healthier, so the claim remain baseless, just something you choose to believe and try to impose to others so they are mislead to taking a bad decision about their health.
No, it is not, this is actually the basis for all public health interventions, you personally not understanding what this is or how important it is for the professionals that take care of the health of the public do not make it outdated, once again this is only something you choose to believe but that has no relationship with what is actually being recommended by the experts.
I mean, when you are unable to bring any health authority that says raw milk is healthier it ends up being their word (and their evidence) against yours (and the absolute lack of any evidence) it is clear who is more likely to be correct, the experts or nameless people on the internet.
The simple fact that the vaccines are approved for use in the population means that the experts in public health consider them safe and effective to be used and the risk they help reducing important enough to be addressed, unless you can prove they are wrong (with actual scientific evidence) their conclusions are simply much more trusts worthy than "trust me, bro" arguments.
Any actual study that prove this has any effect on reducing the risk? specially, that this reduces the risk in the degree that vaccines do? without it your alternative is nowhere near what is necessary to be an actual alternative, specially with the strong evidence of raw milk being a vector of transmission.
Wick's pencil
You'd have a point if they were indoor house cats. But those were cats on dairy farms, exposed to the same bird poop as the cows, and likely eating a few infected birds.
I don't eat raw wild birds, so I'm fine.
Wick's pencil
How do you think the cows got infected. Or how do you think viral fragments (DNA?) got in the milk?
virusrex
No, nothing in the argument depends on the cats being indoors, the arguments are there, it has never been described an outbreak in cats as described in the article, so the possibility even if technically possible would depend on the miraculous finding of something never before being described while ignoring a clear link from milk contaminated with extremely high titers of virus explanined by udders being a main organ where the virus reproduces. This possibility is so strong in comparision that is the only one the authors mention in the conclusion.
Anybody drinking raw milk is exposed so they are not fine, even ignoring influenza.
So you didn't even read the article? the initial infection came from birds, but evidence of horizontal infection is available (with cows in regions not affected becoming infected when cows from affected areas are brought there). Your suggestions would have exactly zero effect preventing horizontal infection, much less reducing the risk of people once human to human transmission is stablished.
Zaphod
Buried in the article:
And since this virus is transmitted via airborne transmission, that should not be a big surprise. The whole article seems more like a big pro-pasteurization opinion piece.
In the event, I do not think that raw milk is available in shops in Japan anyway.
virusrex
That is the whole point of taking measures now, before cases are detected, the problem with antiscientific propaganda is that they oppose preventive measures when they are actually effective only so they can criticize them when they are delayed beyond the point where their efficacy drops.
According to the evidence milk is an extremely likely transmission vehicle that apparently has been enough to even produce transmission cross-species, that means that the risk is enough to merit attention, after all influenza is not exclusively transmitted by airborne particles so milk can be treated as infectious secretions.
When the evidence for the merits of pasteurization are so clear and numerous, this is the default position to take, it like criticizing an article about influenza saying that it feels like a pro-"microbe theory of infection" opinion piece, the benefits of pasteurization are not an opinion, they are fact.
Wick's pencil
That, and another anti-RFKjr-Trump opinion piece.
There is still no direct evidence that people (or cats) can be infected by raw milk.
Just because some milk was found with viral fragments should not be enough to ban raw milk.
Bad Haircut
Gee, these articles designed to demonise everything not produced and pushed by the big food corporations and the friends they fund are coming thick and fast right now. I wonder why?
FWIW, I think raw milk should be allowed to be sold on the market, as long as consumers understand the risks and benefits it provides. Same with the highly processed milk products. As far as I know, we can't get raw milk here in Japan so the point is moot for us here, but milk that's been heated at lower temperature (低温 on the carton) is available in supermarkets, which I get, and has a shorter shelf life but with more of the nutrients preserved.
Of course we have the industry-funded "experts" and their mouthpieces castigating anyone who disagrees with them with the usual ad-homs like "conspiracy theorist, "flat-earthed" and "science denier/antiscience." But the fact remains that as long as the raw milk products are handled properly, consumed within a short period, and the animals are healthy, there's little risk of illness to most people. It seems to me this avian flu find is nothing more than alarmism designed to trigger fear and loss of confidence in a product that the big food corps can't control.
falseflagsteve
Let’s ban people from eating and drinking what they want. Raw milk = NO! McDonald’s, processed muck etc, go ahead Knick yourself out and enjoy.
I’ll take the best alternative anytime, beef and butter, I’ll pay extra for grass fed thanks you kindly
Anyway, if I can buy q litre bottles of fizzy pop, corn snacks and sweets, why can I consume a natural product? Hygiene standards can be checked to ensure safety these days it’s not the 19th century.
Zaphod
falseflagsteve
Well, apparently that is what all the world-wide experts and respected institutions of science are saying. :-)
Mr Kipling
Raw milk is an excellent form of nutrition if you are A BABY COW.
You are probably not a baby cow so why are you drinking milk?
Desert Tortoise
That is not true. There is no scientific data that backs your false claim and lots of scientific data showing that pasteurization leaves the milk with all of its nutrients.
virusrex
That, and another anti-RFKjr-Trump opinion piece.
Again, facts are not opinions, just because you choose to believe differently that does not make all the evidence that points out the dangers of raw milk (and the mistakes of RFKjr) disappear, calling facts opinions only evidence that you have no arguments against them so your excuse is to misrepresent them.
But since raw milk is the cause of an increase of the risk for the population without offering anything over pasteurized milk this measure is justified.
Unless you can refute the scientific basis of the recommendations then you can't claim they are demonizing anything, the evidence is clear so repeating the valid conclusions that this evidence brings is the only valid approach to take.
Most of the scientists have no relationship with the industry yet the consensus is uniform, raw milk is much worse from the public health point of view. Pretending every single institution of the world is in a supposed conspiracy to lie about it is not an argument, it is just an excuse for not having this argument, the same excuse all other antiscientific groups (flat earthers, creationists, etc.) try to use when the evidence disprove what they want to push to mislead people.
Any reference to prove the risk for public health is not higher for raw milk when "handled properly"? because pasteurization is the easiest, simplest form to do that. Rejection is based on irrational beliefs, which unfortunately go together with improper handling precisely because of its irrationality.
So what McDonald's product when consumed makes the person become a risk for others? you understand the special case of infectious diseases right? Why do you think it is forbidden for people working in food preparation to stop washing their hands as instructed?
Commenting again without any source? you are implicitly accepting that your claims are not supported by any institution then.
Jay
Completely wrong. Studies clearly show that pasteurization destroys essential enzymes like lactase, which help digestion, and vitamins such as B2 and C, which are sensitive to heat (MacDonald & Bell, 2010). It also denatures beneficial proteins like immunoglobulins and diminishes probiotics crucial for gut health (Weiss et al., 2011). Raw milk drinkers report better digestion and fewer allergies because the milk's natural properties remain intact (Koop et al., 2012).
Want more? Or are you ready to accept that pasteurization was never about health - it was about extending shelf life and allowing Big Food to monopolize distribution.
Jay
Completely wrong yet again. Facts: multiple studies highlight the unique benefits of raw milk, benefits that pasteurization destroys. A study published in *Frontiers in Microbiology*** (2015) found that raw milk contains beneficial bacteria and immunomodulatory properties, which are wiped out during pasteurization. Another study in The Journal of Allergy and Clinical Immunology (2014) linked raw milk consumption to a drastically reduced risk of asthma and allergies in children, benefits that pasteurized milk simply does not** offer.
Pasteurization doesn’t leave milk 'with all its nutrients'—that’s a myth. Research from *Food Science and Nutrition*** (2019)** shows that pasteurization depletes vitamin C, denatures proteins, and reduces the bioavailability of key enzymes that aid digestion. This process is less about health and more about extending shelf life for Big Dairy profits, leaving consumers with a sterilized product masquerading as 'safe.'
Unfortunately for you, your claim that raw milk is inherently dangerous is outdated and overblown. Modern hygienic farming methods drastically reduce risks, making raw milk both safe and vastly nutritionally superior. Game, set, match.
Moderator
Readers, please don't become obsessed with this topic. Once you have made your point, please move on.
wallace
Tokyo Guy
Usually only within their fields of expertise. Being better educated does not make anyone superior.