In response to my recent blog, Drinking Raw Milk: It’s Not Worth the Risk, we received a number of questions. Here are some of the most frequently asked questions from our readers, along with my answers.

Why focus on raw milk? What about other foods that have made people sick?


We get a lot of questions from people who are trying to decide whether or not to drink raw milk, and we want to provide them with science-based information on the risks of drinking raw milk. 

I work with the group at the Centers for Disease Control and Prevention (CDC) that investigates outbreaks of foodborne illnesses caused by germs like Salmonella and E. coli O157:H7 (a dangerous form of E. coli). Over the years, we have collected extensive data based on experience investigating these outbreaks. Many different foods have been associated with recent outbreaks, such as unpasteurized juice and cider, eggs, and sprouts.

When determining if one food is riskier than another, it is important to understand how many people consume that food. For example, did you know that an estimated 4 percent of dairy products consumed in the United States are unpasteurized, based on a 2006-2007 FoodNet Population Survey, yet more than half of dairy-associated outbreaks are linked to raw milk products?

I know people who have been drinking raw milk for years, and it’s never made them sick. Why is that?

Several things can affect whether or not a person becomes sick after consuming a contaminated food or drink. These include the number and type of germs contaminating the food or drink, as well as the immune defenses of the person who consumes the food or drink.

The presence of germs in raw milk is unpredictable. The number of disease-causing germs in the raw milk may be too low to make a person sick at first, but the germs may later multiply so that there are enough to make the same person seriously ill. As seen in these videos, for some people, drinking contaminated raw milk just once could make them really sick; for others, illness comes after years of drinking raw milk.

I’ve heard that raw milk has enzymes that kill dangerous bacteria. Is that true?

No, the enzymes in raw milk are not strong enough to kill dangerous bacteria. In the United States, pasteurization is the only method routinely used to eliminate disease-causing organisms in milk.

My farmer has set up humane and sanitary conditions for raising his animals and producing raw milk. His animals are really healthy. Doesn’t this ensure that his milk is safe?

Even animals that appear healthy and clean may carry germs that can contaminate milk. Adhering to good hygienic practices during milking can reduce the risk of contaminating the milk, but it doesn’t eliminate it. If the milk is raw, small numbers of bacteria might multiply and grow in the milk before someone drinks it. No matter what precautions the farmer takes, it’s impossible to guarantee that raw milk is free of harmful germs.

What about raw milk that’s been laboratory tested for bacteria?

Negative tests do not guarantee that raw milk is safe to drink. People have become very sick from drinking raw milk that came from farms that regularly tested their milk for bacteria, and whose owners were sure that their milk was safe.

What are the statistics on outbreaks of illness related to raw milk?

Among outbreaks of illness transmitted by dairy products reported to CDC between 1973 and 2008 in which the investigators reported whether the dairy product was pasteurized or raw, 82 percent were due to raw milk or cheese. From 1998 through 2008, 86 outbreaks due to consumption of raw milk or raw milk products were reported to CDC. These outbreaks resulted in 1,676 illnesses, 191 hospitalizations, and 2 deaths.

The data that concerns me the most is about the impact on children: among these 86 raw dairy product outbreaks, 79 percent involved at least one person under the age of 20. These illnesses, which are entirely preventable, can be severe or even life-threatening.

Keep in mind that reported outbreaks represent the tip of the iceberg. For every outbreak and every illness reported, many others occur, and most illnesses are not part of recognized outbreaks.

Can outbreaks be caused by pasteurized milk products?

Pasteurized milk and cheese products can cause outbreaks, but these are usually due to contamination that occurs after the pasteurization process. Also, the most common germ that affects pasteurized milk products is norovirus, which is typically spread from one person to another, not from animals to people. This is different from the germs that can most often contaminate raw milk like Salmonella and E. coli O157 H7, which are spread from animals to people. Also illness from norovirus typically lasts for only 2 days, whereas illness from Salmonella and E. coli is usually more serious.

For more statistics and other information, see Raw Milk Questions and Answers.


This article was initially posted Feb. 28, 2011 at by LCDR Casey Barton Behravesh, DVM, DrPH, U.S. Public Health Service.

  • Terry

    I drank unpasteurized milk as a child. About five years ago, after being sick off and on for years, I was diagnosed with brucellosis. Brucellosis is an intracellular bacteria. This means that the bacteria can actually break through cell walls and destroy cells. It had been living in my body for decades. I have numerous health problems from it including adrenal insufficiency. I am now on disability. So, anyone thinking about drinking unpasteurized milk should really think again. Bad idea.

  • Mike Andrews

    Specious nonsense. As i recall, exactly two people have died in this country since 1998 from raw dairy, due to isolated sanitation issues and/or unrelated pre-existing health problems, while malpractice and prescriptions have now become the number one combined killer in this country, surpassing both heart disease and cancer, which are both still going strong in spite of claims to the contrary. It has also been well known since the 1930s that pasteurized homogenized dairy is one of the leading causes of arteriosclerosis, but the dairy lobby and marketers are very persuasive. As for the brucellosis sufferer, that has nothing to do with raw dairy; it was likely passed to the cow from an infected bison, and would have happened anyway. The fact that you have it at all is an indication that you aren’t so healthy to begin with. As a longtime health fanatic constantly adjusting and engaging in ongoing research into health and longevity, i am living proof that if you are eating and drinking the right things, avoiding dead food and chemical toxins, your body will be healthy as a result, and you aren’t going to get sick, especially from any unadulterated natural product. I consume no alcohol, nor any grain products; I do consume at least three half-gallons of raw bovine colostrum every week, plus raw butter, raw cheese (cow and goat), 2-3 raw eggs daily (plus omelettes on weekends), raw nuts, and plenty of nearly raw grass-fed red meat (beef, bison, kangaroo, elk), as well as chicken, rabbit, pork, and occasionally halibut, with a small amount of non-inflammatory organic fruits and vegetables. In your estimation, i should have died several times already; instead, at 56, i’m in better shape and health than i’ve ever been, or than any of you will ever be, without the benefit of gov’t-recommended ‘safe’ food and ill-advised toxic precautions. I haven’t had so much as a cold in several years, nor the flu in at least twenty-five years, and i hardly live in a bubble. I also have not had a vaccination of any kind since childhood, after contracting three of the five diseases against which i was supposedly being protected. I also supposedly contracted TB at ten, or so the skin test ‘indicated,’ for which i spent 2-1/2 years on Isoniazid, though i didn’t exhibit a single symptom before the test. So go ahead and believe the so-called experts and marketing people, and keep consuming your processed dead foods with the hormones and 3000 chemicals that the FDA allows in them, as well as all the “some possible side effects” prescriptions and OTC products which purport to counteract the effects of that processed crap; you’re all walking science-fair projects. And keep taking your drugs and cooking your brains out; you’re good for the economy.

  • Cara

    FYI … Organic grassfed raw milk kills E. coli and other pathogens. Bacteria in raw milk is a “good” thing … which are called probiotics. What did man do before pasteurization? Do you have any stats on that, a time line … like when the invention of vaccines suddenly started eradicating disease … or did they ?! I’ve seen graphs that show vaccines were initiated “after” an already considerable decline in various diseases. Similarly, milk was just fine “until” a few decided it was a good idea to feed cows the remnants of beer manufacturing and deprive them of grass, turning the milk into a bluish unhealthy pathogen magnetized fluid … not the same milk found in the country where the Mayo clinic recommended its patients go and consume to cure their many respiratory illnesses. Pasteurization was developed to increase profit margin and to create a monstrous dairy industry … the primary goal was “not” to improve the safety of milk. That could have been solved easily by telling people to not consume any of the milk coming from the inner cities. So, today, we have a huge industry built on a lie and millions of people have suffered from the deception … just like the vaccine industry where hundreds of thousands are suffering from vaccine induced injuries and the CDC makes up its own stats to make it look like vaccines are safe, where nothing could be further from the truth. Funny how power and profit sometimes skews the truth of history.

  • Michael Bulger

    The bacteria in raw milk is not protection against E. Coli. That is a fallacy perpetuated by sellers of raw milk.
    Prior to the mid-twentieth century, milk was not a major beverage. Before the twentieth century. few people used their cow’s milk to drink fresh. Instead, much of it went to making cheese and butter. If it was consumed, it was often clabbered. When the early nutritionists declared milk healthy, consumption rose and it was substituted for breast milk in many households. The effects on infant mortality were devastating, leading to the rise of pasteurization.

  • Cara

    The protection factor of raw milk is a theory, but a pretty darn good one! The dairy I get my milk from takes frequent scientific state of the art tests of its products(BSK labs). In the many years since its inception, not one pathogen has ever been detected. Furthermore, private testing (BSK) of the four human pathogens that my state requires testing for: Listeria Monocytogenes, Salmonella, Campylobacter and Ecoli 0157H7 have resulted in showing that even at high levels these pathogens decrease and die. Given its years of not having a single pathogen in its milk it is a fair claim for this dairy to say their milk products are extremely pathogen resistent. It’s premises, equipment and even the cows manure have never shown any pathogens. Can that be said of any conventional dairy that pasteurizes its milk? These dairies are allowed to have 100,000 bacteria per ml before pasteurization and up to 20,000 bacteria (injured, living and even pathogens!) after pasteurization. That in my mind is a bit more riskier than the raw dairy I purchase my milk products from. State standards requires raw milk to have fewer than 15,000 live bacteria per ml and absolutely no pathogens whatsoever! My dairy has an average of 1,500 healthy bacteria per ml and no pathogens!
    Thank you for reminding me about “Clabbered milk.” That is on my list of to do’s.
    I disagree on your interpretation of history showing infant mortality rates as a direct result of mom’s choosing cow’s milk over their breast milk on recommendation of nutritionists of the day. I would like to know where you found that information and if it takes into account the true history of pasteruization. I can understand if those death rates reflected the inner cities (notably New York and Boston) of the 1800s. Unfortunately, these moms must have gotten their milk from the unsafe brewery dairies of the time, where cows were fed beer mush and were kept in filthy conditions with no sanitary milking equipment or refrigeration. Those who milked these cows often were infected with TB and Brucellosis. Can you imagine that happenning today? The resulting milk killed millions including babies and children. Pasteurization appeared to solve this tragedy plus it gave mediocre farmers the ability to pool their not so great milk with others and build a more profitable business for their families. The industry grew, along with Gov’t backing and support$. Today, we have a very unhealthy popualtion that is indoctrinated on the safety and value of killing (pasteurizing, sterilizing) its food. No wonder we are so immune deficient and disease ridden! Our bodies are not being given the building blocks of a healthy gut ecosystem … something that raw milk (under the right conditions) surely provides. I would encourage anyone reading these comments to do their own research and decide for themselves what the truth of the matter is.

  • Michael Bulger

    Based on the fact that BSK labs is located in Fresno, and that you are making McAfee-claims, I’m going to guess your dairy of choice is Organic Pastures. I was recently in LA and was able to pick up some literature that OP prints. I was surprised at how blatantly they are misleading the public. In addition to a few other erroneous claims, the pamphlet stated that OP had never had a positive test for a pathogen. Here you are echoing that claim.
    Explain to me how Organic Pastures can claim this, when they have in fact had multiple positive tests. Here is a positive test and recall due to confirmed Listeria monocytogenes:
    In 2006, six children who had consumed Organic Pastures products became very ill. E. Coli O157.H7 was causing them to suffer from bloody diarrhea. Subsequent testing at Organic Pastures revealed three cows were infected with E. Coli O157.H7. They were a different strain, but the lot of products consumed by the children was all gone, and these were positive tests that indicated infection within the herd.
    Organic Pastures makes unsupported claims regarding their pathogen history, as well as several unsupported claims regarding nutrition and immuno-functions of raw milk. I’d urge you to take another look at the claims of Organic Pasture in light of this, and appreciate them for their role in marketing.

  • Cara

    The Listeria in 2007 was from raw cream from an “outside” source, not Mark’s cows. There were NO illnesses. As for the E. Coli O157.H7 incident … if the e.coli strain didn’t match the one found at Organic Pastures, how can they be blamed for the children getting sickenned? By the way, the State of CA “cleared” OPDC, finding no evidence of linking the dairy to the illnesses … I believe an out of court settlement was made where Mark McAfee was paid by the State. I was a customer during this incident and I have followed the story. I mean, I certainly wouldn’t want to give my family a “tainted” food product, even if I believed raw was infinitely healthier and safer and if I trusted my dairyman. I’ve met Mark. He is a hardworking, honest individual. He is hardly misleading anyone here. The claim of no pathogens is correct … from the listeria coming from an “outside” source (again, there were no illnesses). The E.coli accusation was unsubstantiated. By the way, almost everything has e.coli on it, including you and I! Should we pasteurize ourselves?! Most of the time if we are healthy, our immune systems can handle it. Mark’s cows absolutely did not carry the more dangerous O157.H7 strain and the State knew this after exhaustive testing of milk samples, equipment, cows and manure.
    Please read this link which describes the incident and even what the prosecutor of the case has to say:
    You said there were “multiple” positive tests. I would appreciate it if you could give me those “other” examples. Thanks.

  • Michael Bulger

    Gladly. There is the 2008 recall of Organic Pastures Raw Cream due to detection of Camplyobacter.
    Also, to reiterate, during the 2006 outbreak testing revealed E. Coli O157:H7 in several of Mark’s cows. I will assure you the O157:H7 is not a benign type of E. Coli. All O157:H7 is dangerous. Hopefully, this is not the type you claim you have on you. Pause.
    If that has sunk in, take a look at this link which details the positive pathogen testing on Mark’s business.
    Finally, I’d like to point out that the presence of Listeria in Organic Pastures products counts in my books. It also kind of ruins your theory on raw dairy being naturally protected against pathogens to the point where pasteurization is moot.
    Oh, and would you kindly assist me in understanding why you think the state of California “cleared” McAfee?

  • Cara – regarding OP and the 2006 E. coli outbreak, take the time to read and download all the links, I am sure it will change your mind – facts are good things:—where-there-is-smoke-there-is-fire/

  • Jenny

    After reading all the comments, it is obvious that some of you forgot to notice who was doing the testing here. It was the CDC yep, not someone who just decided to tell everyone about milk. These are highly trained individuals that do this for a living.
    By the way I would never drink milk. We are the only species that drinks the milk of another purposely. Milk is disgusting and the dairy industry is the cruelest I have ever witnessed. A drink isn’t worth all that suffering.

  • Cara

    Gentlemen, why, if Mark McAfee is guilty of all these allegations the State of CA has brought against him over the years, is he still in business? As for the Camplyobacter why did the CDFA say, “At this point, no illnesses have been reported.”

  • Fred

    An actual batch of raw milk tests negative for pathogens and the batch is not contaminated after the testing. Then a human drinks that particular milk. How many people have been debilitated or died in such a case?
    Can anyone provide documentation as to actual events in such an actual case? If there have been such cases, how could that be?
    In all the hot air on this subject, I cannot find the answer to this question. Too many opinions and prejudices, not enough fact.