Is it bad to boil milk?

Question

In another question, I asked about pasteurization of raw milk at home. I got some interesting comments (of course, I further searched on the internet) that some people prefer not to pasteurize raw milk to keep its original flavor and nutrition properties. Pasteurization (whether industrial or at home) at 63 - 72 C will cause a significant loss of vitamins, useful ingredients and generally nutrition values of milk.

Not only for the sake of pasteurization, but also we boil milk for preparing hot drinks. Of course, the boiling point is not necessary, and we let it to cool down a little bit.

Is it really bad to let milk boil? Does it significantly reduce the nutrition values?

Answer 1

So long as we are discussing this topic.

The Center for Disease Control has a specific answer for your question and their answer is NO.

However, According to this paper from the National Center for Biotechnology Information pasteurization causes a breakdown in milk-caesin protein which after uptake through Peyer's patch can promote allergic sensitivity.

There are other controversial claims that the higher temperatures required for milk pasteurization and boiling breaks down some of the ingredients with negative effects. There is a rebuttal to the FDA note from realmilk.com that counters the FDA facts with other scientific papers. However, it's been noted that their paper may not be heavily grounded in rigorous scientific data.

There is a more idepth look in this presentation to British Columbia Centre for Disease Control seems to cover the spectrum of myths based on scientific evidence and critiques. Some of the points discussed are:

• Raw Milk is not a high-risk food (in today's age).
• Raw Milk does have protective properties to allergies and Asthma. also noted in this NCBI paper
• The notion of "the loss of nutrients due to pasteurization is insignificant" is based on an antiquated nutritional paradigm.
• Pasteurization and temperature does reorganize some of the milk proteins, but the effects of that is unknown.

You may wish to watch the presentation, the gist of the discussion start at about 8 minutes in.

In the end, if you believe pasteurization has negative nutritional effects, then boiling raw milk will, too (minus the safety of pasteurized milk).

Answer 2

Significant loss of nutrients during pasteurization is simply a myth.

According to the National Council Against Health Fraud, the loss of nutrients when pasteurizing milk is very small. Most nutrients are unaffected. There is approximately a 10-20% loss of vitamin C, 10% loss of thiamin, and 0-10% loss of vitamin B12.

See the linked article to get their detailed references.

They also mention:

The Family Cow

People who remember "the good old days" when many Americans had a family cow, often ask why they did not get sick from drinking raw milk. The answer seems to lie in the fact that people exposed to the same cow, or cows, on a regular basis develop a conferred immunity to the microflora of their specific animals. It is when raw milk is marketed to the general public who has not been regularly exposed to a specific animal, or small number of animals, that infections occur. Further, the people primarily at risk for serious infections or death are those with undeveloped immune systems, such as babies, or adults with disorders that have compromised their immune systems. Healthy young people and adults who are infected are likely to believe that they have had a bout of "stomach flu."

While boiling milk at home may be somewhat different in its actual outcome, I would suggest that the health benefits of mitigating the risk of food borne illness vastly and completely out weigh any potential loss of nutrients.

Answer 3

Look at it this way: What happens if you boil it, and what happens if you don't?

If you boil, you reduce the risk of getting food poisoning. If you don't boil, you reduce the risk of getting malnourished.

Now, if the temperature-sensitive nutrients in milk are all that stands between a healthy you and a malnourished you, then you are doing something wrong. There are other, better sources of vitamins than raw milk. Nutrients for which milk is likely to be a major diet contributor (calcium, amino acids) are not destroyed by boiling (calcium is an element, you'd need a nuclear reaction to destroy it, and most amino acids are heat stable up to 120 degrees C). So, the risk of actually getting sick from boiling milk is very, very low, even if 100% of the vitamins are destroyed (which seems highly unlikely).

On the other hand, the risk of getting food poisoning from raw milk is low, but it exists. It is not an everyday occurence, but if you consume raw milk regularly, you will be consuming some amount of live pathogens, and they will make sick you now and then (even though most of the cases of food poisoning will be mild, sometimes it will be a serious disease. Some of these diseases kill people despite modern treatment).

Now, there are many people who don't boil their milk. There are good reasons for this, such as taste and convenience. It is a bit like skateboarding: it is not a safe thing to do, but people find it pleasant, and the occasional problem (bruises in skateboarding, upset stomach from raw milk) is worth it from their point of view. As for the more serious risks, they hope that they will get lucky, just like skateboarders hope that they won't break their leg or skull on the skateboard (but of course, there is always somebody who has a skateboard accident, and there is always somebody who gets seriously ill from raw milk - it is a matter of chance). You should decide for yourself whether the taste is worth the risk for you. But from the point of view of pure risk minimizing, boiling (including nutrient loss) is a much better alternative than raw milk.

Answer 4

"It is a bit like skateboarding: it is not a safe thing to do, but people find it pleasant, and the occasional problem (bruises in skateboarding, upset stomach from raw milk) is worth it from their point of view."

I can recall a family where I grew up in northern California that insisted on 'raw milk'. So they bought a cow & enjoyed their own 'raw milk'.

Unfortunately the pregnant mom & 2 small children contracted Listeriosis from the raw milk.

After a 10 day illness the pregnant mom & 2 small children died of Listeriosis.

Listeria monocytogenes is ubiquitous in the environment. The main route of acquisition of Listeria is through the ingestion of contaminated food products. Listeria has been isolated from raw meat, dairy products, vegetables, fruit and seafood. Soft cheeses, unpasteurized milk and unpasteurised pâté are potential dangers.

So there's more than a risk of 'upset stomach' from 'raw milk'.

Answer 5

Raw milk does cause illness in a small number of cases todays (By American National Statistics). But theres is a growing body of research to suggest that its large probiotic content (CFU count and number of strains) improves health significantly if consumed regularly (also beneficial fat content). Skim milk or low fat milk are being found to cause illness because there sugar content is more easily digested and harms insulin sensitivity if consumed regular. All in all, whole milk whether pasteurized or not would be a safer bet according to up to date scientific wisdom (and evidence coming from the dietary habits of some of the worlds healthier cultures). Raw milk, like other milk products such as Kefir, have a host of health benefits we are only beginning to understand scientifically.