By: Candess Zona-Mendola

This installment of The Raw Milk Diaries centers around the hot topic of Pasteurization – pun not intended. Pasteurization has gotten a bad reputation recently as it involves the processing of a food product. In some of the latest food trends, a “back to nature” mantra has inspired people to seek minimally processed food over those that have been properly processed under the proper FDA regulations. What these trend-followers forget is that almost all food purchased from a store has been minimally processed. In fact, when nutritionists typically refer to processed foods in a negative way, they are mainly categorizing foods with added sugar and of the snack variety. These trend-followers further argue that the processing of a food, like pasteurization, removes the nutrients from the food itself, thus making it devoid of any health benefits. Therefore, some opt to instead consume unpasteurized milk, milk products, and juices, leaving themselves vulnerable to dangerous, and sometimes deadly, bacteria.

In an effort to spare you the tummy troubles, I am here to dispel any iota of concern over pasteurization.

What is Pasteurization?

I have previously mentioned that pasteurization is simply heating a food product to kill dangerous bacteria. It is important to note that pasteurization is very different than sterilization – whose sole purpose is to destroy every ounce of micro-organisms in a particular sample.  Pasteurization does not do this. Pasteurization greatly reduces the numbers of bad bacteria and allows good bacteria to remain. In fact, food does not typically undergo a full sterilization process, as this process not only makes the food completely devoid of nutrients, but affects its taste, smell, and even texture. Pasteurization does none of these things. The process itself has some very interesting roots and processes.

What so many people find shocking is that the process of pasteurization is not a new method of food preservation. In fact, the practice is over a thousand years old!

In the 1800’s, Emperor Napoleon III was lamenting the sadness over a spoiled beer or wine he had wanted to enjoy. A French chemist and microbiologist by the name of Louis Pasteur came to his rescue. A pioneer in microbial fermentation and vaccinations, Pasteur new a thing or two about micro-organisms. He soon discovered that, by heating his beverages to a certain temperature, he was able to destroy some of the bad bacteria, hence giving his drinks a longer shelf-life. However, this process was not new. Another Frenchman, Nicolas Appert, was a confectioner and a chef, who discovered that canning (or air-tight food preservation) prolonged a foods shelf-life by many days and even months. In fact, the Chinese have been known to heat their alcoholic beverages for purpose of storage since the 1000s[1].

However, it was not until urbanization and industrialization that pasteurization was found to be a necessary idea. It did not take the early industrialists long to discover that milk was a major cause of disease. During the 1800s, tuberculosis was a common disease spread through milk consumption. It was then that the method of batch pasteurization was used to destroy tuberculosis pathogens. Soon after, the widespread outbreak of tuberculosis dramatically decreased.

In the United States, pasteurization began in the 1920’s and became a common practice in the 1950’s or so. Believe it or not, most public health professionals and food safety experts consider pasteurization to be the greatest food-related invention of all time! Pasteurization has proven so effective in reducing foodborne illnesses in human being from milk consumption, that the CDC, the FDA, the American Academy of Pediatrics, the American Veterinary Medical Association, the National Association of State Public Health Veterinarians, to name a few give it the highest recommendations in keeping one healthy.

What is the process of Pasteurization?

There are actually several different methods for pasteurization, usually depending on what particular liquid is being pasteurized. The below is a very brief explanation of these processes:

  • Batch Pasteurization (low-temperature, long-time (LTLT) process): Similar to the Vat/ Holder method of pasteurization, the process involves heating the milk to 62.5ºC/144.5ºF and holding this for 30 minutes. The concern with this type of pasteurization is that the milk must be consistently agitated to maintain liquidity.


  • Flash Pasteurization (High-temperature, short-time (HTST) process): Mainly used for fruit and vegetable based beverages (with some dairy products) the premise of this method is to heat a liquid for a short period of time – typically in temperatures of 71.5 – 74°C (160-165°F), for about 15 to 30 seconds. This process is so successful that, holistic juice giant Odwalla adopted the flash-pasteurization process in 1996 after its unpasteurized apple juice laden with E Coli sickened many children and killed one. This is also the typical process used to pasteurize cow’s milk.


  • Ultra-Pasteurization (UP): This method is used when a longer shelf life is needed for a particular product. The process begins by heating milk to 125 – 138°C (257 – 280°F) for 2 – 4 seconds and cooling it to less than 7°C (40°F).

Can’t Farmers Just Be Really, Really Careful?

            One of the top arguments of pro raw milk supporters is that all a farmer needs to do is ensure his animals are healthy and maintain sanitary practices in the raising of the animal and the extraction of milk. For those of you who have been around farm animals, I am sure you understand that even the most sanitized processing facilities related to animals are still not perfect. Milk contamination can occur in a wide variety of ways from human contamination on their hands and attire, cow feces (which is known to sometimes contain E Coli among other pathogens) coming into contact with the milk, general bovine disease, animal vectors (such as rats), infection of a cow’s utters, or just natural bacteria on a cow’s skin – to name a few[2]. This is why a sanitary workplace is not one hundred percent effective. Also, a healthy-looking cow may have an infection or a disease without the farmer immediately knowing.

This is why pasteurization is a way to minimize dangerous pathogens from tainting out milk supply, getting us severely sick, and spreading that sickness to the general public. Did you know that raw milk is illegal in some states? It is also such a health concern, that the federal government prohibits the transfer of raw milk between state lines. In fact, it is exponentially more likely for one to contract a foodborne illness related to milk in a legalized raw milk state than one that prohibits the sale of raw milk. Not yet convinced? Stay tuned for the facts and myths of raw milk consumption, coming to a food safety blog near you.

[1] Hornsey, Ian Spencer and George Bacon (2003). A History of Beer and Brewing. Royal Society of Chemistry. p. 30. ISBN 0-85404-630-5. “[…] sake is pasteurized and it is interesting to note that a pasteurization technique was first mentioned in 1568 in the _Tamonin-nikki_, the diary of a Buddhist monk, indicating that it was practiced in Japan some 300 years before Pasteur. In China, the first country in East Asia to develop a form of pasteurization, the earliest record of the process is said to date from 1117.”