Myth: Pasteurization destroys vitamins and minerals in milk

The first thing to understand here is what exactly is pasteurization, and why is it used.

You may have already heard the story: pasteurization was developed by Louis Pasteur in 1864 as he was attempting to discover the cause, and then prevent, the spoilage of wine. He cannot be credited with the initial discovery that microorganisms are responsible for processes such as fermentation, food spoilage, and disease (“germ theory”,) however he can be credited with conducting the scientific experiments that led to this theory achieving widespread acceptance in Europe.

Pasteur also did not determine that heating food would destroy microorganisms (the process of canning, whereby heat treatment and sterilization are used to preserve food for extended periods of time, was developed by Nicolas Appert in 1806), however his contribution was to determine the exact temperature and length of time needed to destroy microorganisms in liquids without changing the taste. Pasteurization at low temperature requires a longer holding time than when high temperatures are used. For example, milk can be heated to 71.7C and held for 15seconds, or at 88.1C and held for only 1 second to destroy the bacteria within. Even higher and lower temperatures/times are used depending on the capacity of the processing plants and the eventual use of the milk. Pasteurization will kill of the majority of pathogens in milk (and other fluids for which the process is used) rendering them safer to drink, and extending their shelf-life.

Pasteurization definitely destroys microorganisms, but the issue is whether it destroys the vitamins and minerals in milk, too. There are many known vitamins and vitamin-like substances, and they all have different vulnerabilities: some are susceptible to light, others heat, others oxidation, and still others are water soluble, getting leeched out when cooked in fluid. Of the most-studied nutrients, only Vitamin C and pantothenic acid are particularly vulnerable to heat. Minerals content is essentially unchanged by pasteurization.

So, yes, pasteurized milk will have slightly fewer nutrients than raw milk, but we really need to consider the trade-off. Pasteurization saves lives. Since the introduction of pasteurization of milk and the corresponding rates of milk-borne illnesses, countries such as Canada, Australia, Scotland and a number of states in the US have forbidden the sale of raw milk. Only a few weeks ago, a new study by the CDC in the US revealed that, between 1993-2006, states where the sale of raw milk is legal had twice the number of outbreaks compared to states where the sale of raw milk is illegal. The study deems that the chance of a milk-borne illness is 150 times higher for a consumer of raw milk products versus someone who consumes only pasteurized products. This has prompted the CDC to issue a warning regarding the consumption of raw milk products in the US.

Personally, there is no question. I’ll take pasteurized milk over raw milk any day. With a varied diet, I know I’m getting all the nutrients I need, despite my milk possibly having a little less than it potentially could. At least I can be quite confident that the milk I drink is safe for myself and my family, and that is far more important.

 

6 thoughts on “Myth: Pasteurization destroys vitamins and minerals in milk

  1. Who are you kidding? Humans can not digest cow milk! We don’t make lactase! Not even adult cows can drink cow milk, only calves make the enzymes needed to digest this milk. Humans need breast milk and then as adults almond milk or rice milk. Get a clue!

    • First, I’d like to thank you for visiting my site and taking the time to comment. While this post is strictly discussing the potential loss of nutrients due to the pasteurization process, and not taking a position on the relative merits or harms of including dairy in one’s diet, I do appreciate your opinion on the subject.

      While it is true that a large swath of the population is unable to digest lactose, that is not the case for all humans. As you said yourself, humans themselves need breast milk as babies; breast milk, like all forms of milk derived from mammals, has lactose as its primary source of sugar. As we age, some of us lose this ability to digest lactose while others will continue to make the lactase enzyme our entire lives.

      Whether we should rely so heavily on milk and milk products in our diet is in and of itself an issue worthy of exploration. There are many arguments on both sides. Perhaps in another post?

  2. Actually there was no such thing as lactose intolerance before pasteurization of milk. So in short people are not lactose intolerant. They are pasteurized milk intolerant.

    • Thank you, Mike, for taking the time to comment.

      I’m not sure I agree with you, however. Most of the world (at least 60%) is actually lactose intolerant, becoming unable to digest lactose between the ages of 2 and 5. In fact, many would argue that it is normal to be lactose intolerant, and the ability to digest lactose past childhood, termed “lactase persistent” is the thing that is unusual. Research indicates that lactase persistence is a relatively new development, evolving about 7500 years ago. You might find this article of interest.

      So, yes, lactose intolerance did exist before pasteurization of milk. Whether pasteurized milk creates other intolerances, I honestly don’t know. I’ve never seen any research on it. so I’m not in a position to comment.

  3. Dr. Arora,
    Does the pasteurization process destroy the enzymes in the milk? My wife is convinced that pasteurized/homogenized milk is ‘bad’ because of what gets destroyed or damaged during these processes. She stated (not sure where she got her info) that the enzymes are destroyed during pasteurization, and then that somehow ‘inhibits’ our ability to digest the milk . . . This may also come from my youngest son, who she says has some lactose intolerance and/or sugar sensitivy – he gets ‘dark circles’ around his eyes when he eats foods with a lot of sugar, but also (according to my wife) when he drinks ‘pasteurized/homogenized’ milk.
    Thanks in advance for any info you can provide.

    • Hi Martin,

      Any enzymes present in milk would very likely be damaged by the pasteurization process. Enzymes are proteins, and heat denatures proteins (which means they change their shape); this type of damage would prevent them from functioning the way they are supposed to.

      That said, I don’t think your son’s problem with milk has anything to do with enzymes that may or may not aid digestion. it does sound like your son has some sort of intolerance to sugar, if consuming a lot of it leads to dark circles around his eyes, but it is no surprise that milk causes the problem as well. “Lactose” in milk is another type of sugar. Table sugar is “sucrose”, fruit sugar is “fructose” and milk sugar is “lactose” (anything ending with “-ose” is a form of sugar). Is your wife comparing your son’s reaction to pasteurized milk versus raw milk? Or versus cheese and other forms of dairy? I’d be surprised but interested if your son has tried raw milk without difficulty (though as I mentioned in my post, I don’t recommend it for safety reasons)

      I’d expect cheese would be consumed without a problem. The way cheese is produced leaves it with very little lactose in the final product, so your son should be able to handle it far better than straight milk.

      I hope that clarifies things for you. BTW, I wish I could say I deserved the honorific, but I’m not a doctor, nor do I feel the need for formalities. Feel free to call me Renu. :)

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