How to Pasteurize at Home


| August/September 1998



Raw milk and your health. 

Well, the seasons continue to march along, and the dog days of summer are nearly over. As I drive from farm to farm, it is a never-ending source of joy to see the foals, calves, and lambs growing and frolicking in the pastures and to see the progress of this year's field crops growing to maturity. Veterinary medicine is a source of endless challenges, both physical and mental. If I accurately diagnose a sick animal at a farm, I turn around and am faced with questions from the owner that keep me thinking. Recently, I was faced with a question that was the impetus behind the topic for this article. A client had a goat that was the source of milk for herself and her young children. Her goat was diagnosed with a disease that is known to be transmitted in both cow and goat milk and she and the children had been drinking the goat's raw (unpasteurized) milk. She was concerned about contracting the disease and asked about the risk of infection to herself and her children.

The topic of raw versus pasteurized milk is a controversial one that always stirs up heated discussion. Many farm dwellers and food purists find raw milk more delicious and perhaps more nutritious than pasteurized milk. As a veterinarian, I took an oath to protect the well-being of animals and to ensure a safe food supply for humans. The drinking of unpasteurized milk should be an informed choice. There are hazards associated with the consumption of raw milk and there are effective methods of pasteurization available for home use. The sale of raw milk is a very small local market available to a small number of dairies that are required by law to adhere to very stringent sanitary requirements. The sale of raw milk is prohibited across state lines within the United States, but almost half of the states permit the sale of raw milk within state borders. The USDA has passed these regulations because of the known hazards associated with consuming raw milk. Pasteurization of milk was begun initially to prevent the passage of two important diseases from animal to humans through raw milk: brucellosis and tuberculosis. There are regions of the United States where these diseases have been eradicated through vigilant efforts by the government, producers, and veterinarians. So it may seem that the necessity for pasteurization of milk is antiquated; however, there exists an ever-growing number of additional infectious agents that have been isolated in raw milk.

There are two categories of diseases that are potentially transmitted in raw milk. The first category includes those causative agents that are secreted in the milk directly from the mammary gland. The second category includes fecal contaminants in milk. Many of these are not serious in immune-competent, healthy people. But babies that are chronically ill, older people, pregnant women, people infected with HIV, and those receiving cancer therapy are less able to withstand infection by such organisms and are more susceptible to disease. The American Veterinary Medical Association has taken a stand against the sale and consumption of raw milk. When raw milk is used in cheese production, a test is run on the milk to test for actual numbers of bacteria. This screening detects any lapses in sanitary procedures during milking which could lead to the increased possibility of potentially dangerous fecal contaminants in the milk. This is a protective measure required by law in the production of cheese because many soft cheeses are made with raw milk. Zoonotic diseases are those that are passed from animal to man. Ringworm, brucellosis, and E. coli are just three better known examples of such diseases. There are many zoonotic diseases potentially transmitted in raw milk. Some of these include: brucellosis, listeriosis, Q fever, cryptococcosis, leptospirosis, louping ill, meliodosis, staphylococcal food poisoning, toxoplasmosis, and tuberculosis. Many others are passed in raw milk through contamination of milk with feces containing the following bacteria: Campylobacteria, Escheriacoli, Yersinia, Salmonella, Cryptosporidia, and Listeria. The intent of this article is not to expound on the numerous potential pathogens that are found in raw milk, but rather to educate about the hazards of raw milk, and provide ample information to enable the home consumption of safely and accurately pasteurized milk.

Milk is the ideal host for many spoilage organisms, and pasteurization will increase the shelf life and decrease the bad flavors produced by such organisms. Pasteurizing milk is very simply the heating of milk to a specific temperature for a specific time to kill the microorganisms that can transmit disease to humans. The source of these bacteria varies widely; they can be excreted directly into the milk by the animal, they can come from fecal contamination of the milk, from contamination of the milking and storage equipment, or even from the handler of the milk.

The process of pasteurization dates back to the work of Louis Pasteur between I860 and 1867. He was also the inventor of the vaccine against rabies. Pasteurization and proper handling of the milk, in addition to destroying the potential disease causing bacteria, can greatly increase the storage life of milk by inactivating the enzymes, elements in the milk responsible for rancidity. The process of pasteurization does NOT significantly alter the nutritional content of milk.

lisa zandt
8/29/2011 11:40:28 AM

Very disappointed in the article!! I am supposed to just take your word for it that Pastuerizing does not take any of the nutrients from my raw milk. I have read and talked to hundreds of sources that say differently. I was looking for the other side but apparently there isn't one. Just an opinion. Maybe all of that got lost in editing? along with the proper proceedures you refer to in the last paragraph. You have altered my opinion of this magazine with just one article.

dr. akalpita paranjpe
10/2/2010 5:03:07 PM

I am an Indian brought up in a small city. We always used to have a cow and a buffello in our house. We drank milk strainght as it was milked (in our own glass by ourselves). In india even today, we get fresh milk daily. Traditionally, we boil milk every day before using it. We always add hot milk to our tea/coffee. Our cows are always fed on grass/hay or fodder of vegitable origin. Where ever possible, they graze in jungles (forests) where they get a variety of green food of their choice. Though we do clean the animal before milking, we use cow dung as well as cow urine for medicinal purposes. In our childhood, we used to clean our hands with cow dung after toilet. We always used cow dung for keeping our floor clean as we used to sit on the floor for eating. Even today we prefer houses where the floor is pasted with cow dung, except for the fact that it is difficult to maintain. We never consider fresh cow urine or fresh cow dung bad for health. Infact, cow urine is also used for making a spray for organic paste control. Akalpita

david mccartney_2
7/23/2010 7:57:32 PM

I was raised on a dairy farm and my parents always gave us pastuerized milk. Once I took over, we drank raw milk. My kids drank raw milk from toddler age and were never ill. In fact they never saw a doctor until we moved from the farm and started drinking store bought milk. I think a lot of comments get posted by people stating what they have heard rather than the facts or truth. I have been on dairy farms that are so clean you can eat off the floors. It doesn't cost any more to run a clean dairy. I have also been on farms that were the opposite. Where would you rather buy your milk from?

jennifer webb_2
1/26/2010 10:51:27 PM

I agree with Jan. However, this is one fine example of our education system passing on information without providing the entire story, and professional medical journals being cited in the best of intentions but retrieving material that erroneously manipulated Dr. Francis Pottenger's findings in his cat studies. Words are carefully twisted as to not actually LIE, but serve the author's purpose, nothing new by any means! Dr.Pottenger wasn't just some guy; check it out, you would be surprised at what you find out about how we got to the state we are in today in this country with our dairies. What about the work of Weston Price? So much is left out;people accept what they are taught.What about many of our naturopathic physicians in this country who prescribe raw milk to people with certain ailments such as allergies, and they improve? I understand there are pathogenic risks, which is why our nation's system needs major change. Scientific research can help find vaccines for some pathogens, making raw milk more appealing to the public. Education and research can work to change ideas so many in professional positions of authority (such as veterinary and medical doctors)and the public to see the benefits of raw milk and its healing nutritive properties, and expect healthier cows, healthier living conditions. Many of the pathogens including Johnes disease are caused by unsanitary living conditions: I find it surprising that the animal activists haven't jumped all over that one!

jan steinman
12/31/2009 3:50:21 PM

Congratulations to Dr. Barnes for maintaining a civil, if uninformed, attitude regarding "real milk." But I do find much of her argument to be faulty. In my experience, carefully harvested raw milk lasts longer than pasteurized milk. We routinely have milk last for two weeks and sometimes longer. The enzymes she decries are a feature, not a bug! Don't "kill" your milk! But more distressing is the "failure mode:" raw milk ferments, while pasteurized milk rots. As Dr. Barnes notes, milk is an ideal medium for bacterial growth. By indiscriminately killing everything, pasteurization makes milk an available feast to all manner of opportunistic micro-organisms. But raw milk's natural flora of human-friendly lactophylic bacteria out-competes pathogenic bacteria, and you end up with sour milk, suitable for baking or cheese-making, instead of a putrid mass of wild bacteria and fungi. Pasteurization became the standard during the days of "swill dairies." Distilleries had an endless supply of spent mash, and setting up a dairy next door was for them an ideal solution. However, it is not a healthy diet, and the dairies were not well-kept. This made pasteurization necessary to clean-up a defective product. Although outlawed a century ago, incredibly, this is happening again, with ethanol factories once again supplying "swill dairies." Get ready for more sick milk. Please visit for the other side of the debate.

8/5/2009 10:04:23 AM

Finally someone with a little common sense! Anyone that believes that milk producers and milk companies pasteurize as a cost savings is more than a little loopy! It is simply NOT true. As someone that has had a loved one with TB don't risk it. She had contracted the disease many years ago, it encapsulated and didn't present until she was in her 80's. The one year of enforced isolation was devastating to her. To the point of the article, if you drink unpasteurized milk, you may as well know what you are in store for. Unless that cow is forced to stand in one spot on concrete, with a cleaning system at her feet, there will be fecal matter that will be on and IN the teat. Nothing that can be done about it.

10/4/2008 7:52:38 PM

Heat milk to 161 degrees F for at least 15 seconds, agitating to ensure milk is entirely heated, even the foam must reach 161. Microwaving doesn't work due to uneven heating. Use good food thermometer, and clean kitchen techniques to avoid recontamination after pastuerization.

9/24/2008 8:38:09 PM

I do wish this article was more true. The reality is that producing pasteurized milk is cheaper for the farmers and the dairy because they do not have to maintain a clean production facility as carefully. Unfortunately, outbreaks of disease from consumption of pasteurized milk are far too common and have affected millions of people in the years since the processing was made mandatory. It is a crime against the public that we do not have freedom of choice about what milk we drink. Informed choice, yes, but free choice, absolutely! Pasteurization destroys many of the best things in milk, and homogenization furthers the damage. I'm disappointed in one of my favorite magazines for taking the mainstream position and missing the truth altogether.

1/5/2008 1:13:39 AM

This article title is "How to Pasteurize at Home" but it does not tell me how to pasteurize at home which is the reason I read the article. The rest of the article contained great info. Thank you.

12/9/2007 9:31:04 AM

Where is the rest of the article - the how-to part?

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