It is hard to get infected. The immune system is robust and has a multitude of interlinking defenses that are extremely efficient in beating off most pathogens. Most of the time.

Fortunately, it is a minority of microbes that have evolved to be virulent in humans. Bacteremia is common with our own microbiome. When you brush or floss, bacteria leak into the blood stream:

We identified oral bacterial species in blood cultures following single-tooth extraction and tooth brushing. Sequence analysis of 16S rRNA genes identified 98 different bacterial species recovered from 151 bacteremic subjects. Of interest, 48 of the isolates represented 19 novel species of Prevotella, Fusobacterium, Streptococcus, Actinomyces, Capnocytophaga, Selenomonas, and Veillonella.

but with a good immune system, low virulence bacteria and no place to go, unfortunately the bacteria rarely cause infections.

Even heroin users rarely get infection. Heroin is a rich melange of bacteria and, on occasion, yeasts (I hate to say contaminated, since avoiding microbes is hardly a worry of heroin manufacturers), and the water used for injection is rarely sterile, yet infections are relatively rare despite the filth in which many heroin users exist.

I used to be somewhat fatalistic about hospital acquired infections. However, as the institutions in which I have worked have proven, almost all infections in the hospital are preventable if the institutions aggressively pursue high standards of care.

There are many systems in place in society to prevent infections: flush toilets, good nutrition, public health, vaccines, antibiotics, good hygiene, and an understanding of disease epidemiology, and I suspect people forget there are bugs out there that are pathogenic, just waiting to sicken and kill us. At least a couple of times a year I see patients come into the hospital, previously healthy, who rapidly die of acute infections.  But for most people, most of the time,  it takes a lot of effort to get an infection.

From my perspective we are Charlie Chaplain on skates , mostly unaware of the infections that awaits us if we do something silly, or even when we act with the best intentions to avoid illness. The odds are small we will get a life threatening or serious infection in the US, just as the odds are small we will drown or be killed in a car accident. The germs are there, waiting, and in the end, no matter what we do, we will be consumed by the microbial world.

It is that perspective that leads to a lack of understanding as to why some people seem to love tipping the odds in favor of the bacteria. Avoiding vaccines is perhaps the most popular method for getting infections that could otherwise be avoided, but dietary habits are an curious way to acquire preventable infections.

Humans and cows have a long history of sharing infectious diseases. Measles is either a variant of rinderpest, a cattle illness, or they share a common ancestor. On the beneficial side of the relationship was cowpox, which lead to the smallpox vaccine.

While I am a bit of a foodie (for example, while I do not remember by first kiss, I remember the epiphany of my first gourmet restaurant meal), I cannot grok (see how old I am) people who either think a specific food is to be avoided at all costs or is the panacea for preventing illness. Like cows milk.

There is school of thought that cows milk should be never be consumed: it is filled with pus, blood, hormones, foreign protein and antibiotics. And not only does milk not build strong bones, it leads to cancer. And if you can’t trust a kinesologist, who can you trust?

It’s not natural for humans to drink cow’s milk. Humans milk is for humans. Cow’s milk is for calves.

Sounds like a metaphorical argument for cannibalism to me.

And, as the anti-cows milk proponents note,  milk has infectious diseases swimming in the white murk. A cesspool of bovine feces and bacteria that should be avoided, although how you can eat a homemade chocolate chip cookie without it, I cannot imagine.

So milk is one of the bad foods and should be avoided. Except when you shouldn’t. Newtons Law states that for every SCAM, there is an equal and opposite SCAM. Milk is dangerous, except when it is a panacea, when the milk should be raw milk, fresh from the organic, happy, contented cow.

Why raw milk? Pasteurization and homogenization rids the milk of the beneficial components: white cells, proteins, lactoferrin, immunoglobulins, fats, cholesterol and bacteria, curiously all the substances that the anti-milk faction says are the root of milky evil. I suppose that, for a raw milk aficionado, there would be no greater dietary sin than a warm glass of milk at bed time or a cup of hot chocolate after skiing.

The truth? I do not doubt that flash heating (usually to 165 degrees for 15 seconds) is going to have some nutritional effects on the milk and, if my diet consisted entirely of milk, it would be a concern. However, what small decrements in nutritional value occur would, and should, be made up with a varied diet. Milk is not, unless turned into Baskin Robbins Chocolate Chip ice cream, a miracle food. I also have no reason to doubt that there is a subset of people who have allergic issues with cows milk. Not everyone can drink bovine proteins with impunity.

Taste, of course, is a personal matter, and I cannot gainsay those who say raw milk tastes better. In my family everyone is picky about their milk; it cannot come in plastic and has to be a specific brand, Dairygold. My wife insists Oregon milk is inferior in flavor to Minnesota milk. French milk tasted weird, and I thought everything else tasted better in France. Pasteurization has mild effects on the nutritional components of milk, and perhaps the taste.

But what raw milk is, above all,  a source for infection. There have been outbreaks with Campylobacter, Salmonella, E. coli associated with raw milk and other organisms can be found in raw milk, some not common in the US, including  Brucella, Listeria, Mycobacterium bovis (a cause of tuberculosis), Salmonella, Shigella, Yersinia, Giardia, and norovirus. Some are found in cows milk, and some, such as Brucella, more common from goat’s milk. These outbreaks have lead to hospitalizations and a few deaths.

Warm liquid filled with protein, fat and sugars. A good growth media for a bacteria, if they can gain access to the milk. Impossible. Proponents of raw milk point to the clean cows and clean environments that produce raw milk, but you cannot deny both microbiology and gravity. The colons of cows are frequently colonized with the aforementioned potential pathogens and the udder sits below, waiting to be splashed with cow pie. MMMMmmmmmm. Milk and pie. Seriously. Would you lick any cow udder, no matter how clean?

Still, people want their raw milk for the taste and health benefits. Some obtain raw milk illegally at milk speakeasies where I bet the password is Swordfish. You can time share a cow and get the milk straight from the source, although you have to see a presentation on time sharing cows to get the free weekend on the farm. This is good news for me. Since we have instituted aggressive infection control at my hospitals nosocomial infections have plummeted. Once upon a time milk was associated with 25% of infection outbreaks; in part due to pasteurization those rates fell to 1%. Thanks to the raw milk advocates, infections are looking up. The sad thing is parents will feed their children milk supplemented with cow poo. Adults have the right to be stupid; it is what makes America great. But it is a shame that children should suffer as a result of their parents goofy idée fixe.

There is a tendency for humans to have the oddest dietary obsessions, both for and against.

God told Moses certain animals were “clean” to eat — those with cloven hoofs which chewed the cud such as cattle, goats, sheep, deer, and so forth. All fish with fins and scales, and insects of the locust family were also “clean.” The pig and the camel, however, were “unclean” and were not to be eaten. All carnivorous birds, sea creatures without fins and scales, most insects, rodents, reptiles, and so forth were “unclean.

Milk is not on the list. Milk can be an enjoyable part of a diverse diet for most people, but like most foods it should not be filled with live organisms. Pasteurization is a good thing. Except for Hefeweizen. Give me my raw beer.



  • Mark Crislip, MD has been a practicing Infectious Disease specialist in Portland, Oregon, from 1990 to 2023. He has been voted a US News and World Report best US doctor, best ID doctor in Portland Magazine multiple times, has multiple teaching awards and, most importantly,  the ‘Attending Most Likely To Tell It Like It Is’ by the medical residents at his hospital. His multi-media empire can be found at

Posted by Mark Crislip

Mark Crislip, MD has been a practicing Infectious Disease specialist in Portland, Oregon, from 1990 to 2023. He has been voted a US News and World Report best US doctor, best ID doctor in Portland Magazine multiple times, has multiple teaching awards and, most importantly,  the ‘Attending Most Likely To Tell It Like It Is’ by the medical residents at his hospital. His multi-media empire can be found at