Why Pasteurize Milk?

Darigold Milk, 1956 & 2012

Darigold Milk, 1956 & 2012

By Cat, Jun 2007 (Photo, right, from Wikimedia Commons)

Raw milk provides many healthful benefits, much of which is lost with pasteurization. This is discussed in more detail in Raw Milk: A Real, Raw, Natural and Perfect Food, but what follows is a summary before addressing the other topics in this article.

  • See also: 1Whole Foods Menu2. Food Safety & Pasteurization; Other Sites: Real Milk.com
  • Includes: 1. Raw vs. Pasteurized Milk: 2. Why is milk pasteurized? 3. What Are the Bad Bugs, and How Do they Get Into my Milk? 4. Health Consequences of Consuming Pasteurized Milk; 5. Denatured Proteins: Birth of an Allergy; 6. Rancidity: A Result of Pasteurization

Raw vs pasteurized milk, a summary



Benefits of Raw Milk:

  • As a perfect food, it has nutritional value, providing vitamins, minerals, carbs, fats and proteins readily available for digestion and absorption;
  • It provides enzymes to help us digest our meals and assimilate the nutrients;
  • It has immune-protective value, protecting us from infection by bacteria, fungus, virus, protozoa, and worms;
  • It may have some hormonal benefit, supporting the thyroid, prostate and pancreas.
  • Buttermilk cultured from raw milk has been used for centuries to preserve meats, to last many years.

None of these benefits survives pasteurization.  NOT ONE.  During pasteurization:

  • Milk’s proteins are denatured, which can lead to allergies;
  • Its fats are oxidized;
  • Vital enzymes and antibodies are deactivated, including the enzyme that makes milk’s minerals like calcium and phosphorous available(thus your body cannot absorb the minerals);
  • Fat soluble vitamins A, D and E are greatly reduced; vitamins C, B6 and B12 are destroyed;
  • The friendly, living, health promoting probiotic bacteria are killed, encouraging the growth of pathogens (bad bugs).

Why Is Milk Pasteurized?  

We all learned in Science class that Louis Pasteur discovered the process (bearing his name) that kills infectious bacteria present in raw foods such as milk, fruit juices, beer, wine, and vinegar.  This process involves heating the raw substance to a certain temperature that is fatal to the bacteria, supposedly making the substance safer for consumption.  For milk, this means heating to a minimum of 145°F and keeping at that temperature for at least 20 minutes (or less time if heated to a higher temperature), then reducing the temperature to not more than 55°F (4).

And indeed, in the 1920s when pasteurization of milk became common, it did reduce the incidence of certain diseases in infants and adults who consumed milk.  However, this improvement reflected the coverup of bad dairy practices (filthy conditions, improper feed, sick animals, etc.), not any assumed unhealthful qualities of raw milk.

As science learned more about the nutrient molecules present in milk, it also learned that the pasteurization process introduced other problems with far reaching consequences that, to this day, are blamed on problems other than the pasteurization of milk.  (Refer to the section titled “Health Consequences of Consuming Pasteurized Milk” below for more on this subject).

And yet, we continue to believe that pasteurization is necessary to keep us safe.

The commercial milk lobby has worked hard to foster this belief, especially within our  government; we fear raw milk like we fear terrorists.  Why do they want us to be afraid?  Because it allows them to maintain their grip on this entire market.  In the last half of the 20th century, small and local dairies consolidated to save costs; eventually selling out to the larger commercial dairies who could ultra-pasteurize the milk to extend the shelf life of the milk.

This extended shelf life allows the milk to be warehoused in a central location then trucked across the country, thousands of miles in many cases, from processor to consumer. (Raw milk would sour if warehoused and then transported across such great distances).

However, this is changing in the 21st century, as people are rediscovering the value of locally produced raw foods (as opposed to industrial processed foods).

What Are the Bad Bugs, and How Do They Get Into My Milk?

Natural milk in the mother’s breast is rich in nutrients and probiotic microbes. Probiotics are beneficial to the health of the infant (and other consumers of the milk), imparting immune protection and other benefits.  These good bugs actually prohibit the growth and proliferation of pathogenic (bad, disease-causing) bugs. Thus clean, raw milk is free of pathogens under normal circumstances, and certainly no one would suggest pasteurization of human mother’s milk before feeding her infant. And the same is true of cow’s milk.

But exposure of the milk to a contaminated environment during or after milking, introduces many pathogenic bacteria and other microbes to the milk, such as:

  • Salmonella
  • Tuberculosis
  • Listeria
  • Brucellosis
  • Typhimurium
  • Campylobacter
  • Mutated E. coli (note that not all e. coli is pathogenic; only mutated versions from the guts of cattle fed a diet of corn and soy)

If the udder (breast) is not cleaned prior to milking, it may be contaminated with many bacteria from the cow’s excrement, or from the cow’s bedding.  Contaminated milking equipment or storage equipment can also infect the milk.

The good news is that if the dairy animal(s) are healthy, their milk is full of good bacteria – probiotics –  that can successfully attack and eliminate the foreign invaders that would like a new home in the milk. They key, here, is “healthy” dairy animals. If they are ill, their immune system can be compromised, and that could mean they have insufficient good bacteria to protect the milk. Cleanliness is the first step toward healthiness. It’s companion step is clean, healthful feed native to the animals’ natural diet.

How milk came to be pasteurized

Indeed, the reason pasteurization of milk was initially introduced, is because the conditions in urban dairies in the late 1890s and early 1900s were decidedly unclean.  This filthy milk exposed consumers to  infant diarrhea, undulant fever, salmonella and other diseases caused by poor animal nutrition and dirty production methods.  It was also believed that cows carried TB, which could be passed to humans through cow’s milk (this has since been disproved).  The dairies opted to pasteurize rather than clean up their act.  The public was skeptical about this processed product and had to be convinced to choose it over raw milk.

Fear that raw milk harbors TB was probably the biggest factor that led to widespread acceptance of pasteurization in the 1930s.  The fear persisted, despite extensive testing of raw milk samples that has yet to find the tuberculosis bacteria in clean raw milk; despite extensive experimentation on animals that demonstrate that clean raw milk does not carry this bug.

Indeed, it has been established that raw milk can actually provide immune protection from this terrible disease (reported in the Lancet, p. 1142, May 8, 1937). (3)  Raw milk has also been used to improve the health of persons afflicted with TB. (1)

And now, 100 years later, most people believe that raw milk is unhealthy. While this may be true of raw milk from CAFOs (Confinement Animal Feeding Operations), raw milk from a small local dairy farmer who feeds his family on the raw milk from his cows is clean and healthful. Also, while commercial  dairy processing facilities have, for the most part, cleaned up their act (using modern stainless steel tanks, milking machines, refrigerated trucks and inspection methods), most ultra-pasteurize their milk to extend shelf life and allow long-term warehousing. And this degrades the nutrient quality of the product. (2)

Health Consequences of Consuming Pasteurized Milk

It is now known that the consumption of pasteurized milk instead of raw milk can lead to, or exacerbate existing health problems, such as (1, 2):

  • asthma;
  • allergic skin problems (such as eczema & psoriasis);
  • digestive problems (constipation, diarrhea);
  • hay fever and environmental allergies;
  • reduced resistance to diseases such as TB, scurvy, flu, diphtheria, pneumonia, tooth decay;
  • reduced calcium absorption and impaired growth in children;
  • osteoporosis;
  • arthritis;
  • heart disease.

Vitamin A, D and E content is reduced by up to 66%; vitamins C, B12 and B6 are destroyed; and beneficial probiotic bacteria are killed.  Calves fed pasteurized milk do poorly, and many die before maturity. (2)

Lipase, an enzyme that breaks down fat molecules, is one of the enzymes destroyed by pasteurization.  This impairs fat metabolism and the ability to properly absorb vitamins A and D (the fat soluble vitamins).  Because of this, the dairy industry fortifies pasteurized milk with vitamins A and D, often using synthetic, less active forms of these vitamins (1).

While raw milk is a wonderful source of available calcium, pasteurization makes calcium (and other minerals) less available. In order for the body to absorb calcium from ingested foods, the enzyme phosphatase must be present.  But pasteurization completely destroys this vital enzyme (1). 

Denatured Proteins:  Birth of an Allergy

Protein molecules are long (sometimes very very long) chains of amino acids.  These long chains bend, spiral, and twist into a specific configuration that is recognized by the body as “friendly.”  This shape is essential to the purpose for which the protein is created. The recognizability of the shape keeps the body from creating antigens to fight it off as a foreign invader.

Sometimes, in the course of doing their work, the protein shifts into another shape, which is also recognized by the body as “friendly.”  An example of this is hemoglobin, the protein that carries oxygen through the blood.  It has one shape when it is carrying an oxygen molecule, and another shape when it is waiting to pick up an oxygen molecule; but both shapes are natural and recognized as “friendly.”

However, exposure to heat, pressure, or certain chemicals can cause the protein to unbend and shift into a position that is not bio-active (cannot perform the function for which it was intended). Such a protein has been denatured, or, in other words, stripped of its biological ‘nature.’  The body doesn’t recognize this new shape as “friendly,” and mounts an allergic response, producing antigens to neutralize the threat.  A new allergy is born.

Milk allergies from pasteurization

When milk is pasteurized, or milk’s casein and/or whey protein fractions are heated and dried, they become denatured.  When you ingest these substances, your body mounts an allergic response, and you become allergic to that substance thereafter.  So, whenever you see “non-fat dry milk” or “powdered skim milk” in a list of ingredients, avoid that product or risk provoking an allergy.

A note about whey protein powders:  Most whey protein powders are denatured. Look for brands that do not use pasteurized milk, and that use low temperature/low pressure processing to avoid allergens. My favorite is Bob’s Red Mill Whey Protein Powder, as it is processed and dried at low temperature. It is the only protein powder I’ve tried that doesn’t give me a stomach ache.

Rancidity:  A Result of Pasteurization

When you hear the term ‘rancid,’ do you think of something that has a bad odor because it’s old and should be thrown away?  Good, because that is exactly what you should do.  But just what does rancid mean?  And what does it have to do with milk?

Fat molecules, like proteins, are sensitive to heat and pressure.  They too have twists and bends in their configuration, exposing certain molecular bonds to the action and/or protection of enzymes, vitamins, and cofactors.

The fats most sensitive to rancidity are the poly-unsaturated oils, such as corn, soy, canola, sunflower and cottonseed oils; this is because the double bonds (that make them unsaturated) are readily oxidized (react with oxygen to form free radicals).

When these fats are exposed to heat and/or pressure (as during pasteurization), their configuration shifts, exposing the bonds to the action of oxygen and other oxidizing agents (oxidized cholesterol, peroxides, free radicals) and glycating agents. This oxidizing action changes the chemical makeup of the fat molecule, creating free-radicals. These free-radicals then go on to oxidize more fat molecules. They can even cause the molecules to split into 2 or more smaller molecules, or to combine with other molecules to create molecular monsters (such as A.G.E.s, Advanced Glycation Endproducts). This oxidation of fats is called “rancidity.”

None of these oxidized and glycated products is recognized by the body as ‘friendly.’  The body mounts an inflammatory response whenever these oxidized products are present.  If the inflammation persists, dangerous conditions can develop; for example, high blood pressure, coronary heart disease, heart attack, stroke, and arthritis, to name just a few.

While milk is not abundant in poly-unsaturated fats, those that are present are still vulnerable to oxidation, especially in the absence of the protective vitamin E (that is destroyed by pasteurization). When butterfat is pasteurized, ultra-pasteurized, or otherwise exposed to heat and pressure (such as in the drying process), those vulnerable fats become oxidized, or rancid.  And like any other rancid product, it should be thrown away, even if it doesn’t have a bad smell, because it is a poison.


  1. Weston Price website: 1a. westonaprice.org/children/rawmilk.html; 1b. westonaprice.org/transition/dairy.html
  2. RealMIlk website: 2a. realmilk.com/what.htmlrealmilk.com/where.html; 2b. realmilk.com/raw.htmlrealmilk.com/homogenization.html, and 2c. realmilk.com/rawvpasteur.html (was #5)
  3. karlloren.com/aajonus/p15.htm (Link no loger valid)
  4. Mercola’s website: 4a. mercola.com/2003/mar/26/pasteurized_milk.htm, and 4b. mercola.com/2002/feb/27/rbgh.htm, and

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