By: Christopher Labos MD CM FRCPC
While I was down in the US recently, I discovered that one of the great debates going on that country is whether producers can sell unpasteurized milk. Raw milk has become the fad du jour with advocates claiming that it is safe and good for you. Sadly, neither point is true.
To understand the debate we have to go back to the beginning of pasteurization and to one of the greatest scientists of modern times, Louis Pasteur. Interestingly, Pasteur’s initial work had nothing to do with milk but with wine. He was commissioned to figure out why wine spoiled and turned to vinegar. He discovered that tiny microscopic organisms were present in the wine and caused it to spoil. It was the birth of the germ theory and the founding of a new field of medicine, microbiology.
To be fair, Pasteur didn’t actually invent the idea of heating a substance to kill the bacteria inside, that honour belongs to Nicolas Appert. However, heating a liquid to boiling would frequently change the taste of the wine and give it a more acidic flavour. Pasteur determined the optimal temperature and time required to kill the bacterial contaminants without affecting the taste. So French wine was saved, and the process became known as pasteurization in his honour.
It was Franz von Soxhlet, a German chemist, who first suggested in 1886 that pasteurization could be applied to milk. At the time, and into the early 20th century, milk was a common source of food borne illness, particularly tuberculosis and brucellosis. As a result of pasteurization and a policy to slaughter TB infected cattle, bovine tuberculosis fell drastically. While prior to 1917 it accounted for somewhere between 20-30% of TB cases, it now accounts for about 1%.
The main theme of the raw-milk lobby is that raw milk is safe, and that the bacteria in raw milk are the “good” bacteria. In fact, pasteurization was applied to milk specifically because it wasn’t safe and often transmitted disease. The raw milk literature often makes semi-scientific claims like “Staphylococci, Streptococci, Lactobacillis and Ent. faecalis in raw human milk inhibit pathogenic Staph aureus.” Clearly there is a lack of understanding here as Staph, Strep, and Enterococcus infections are very common and can be very dangerous if left untreated. If they had seen what I’ve seen, namely someone developing meningitis from a listeria infection they would sing a different tune.
The second major claim of the raw milk people is that pasteurization damages the milk and removes the health benefits. Well first off, you don’t really need milk to be healthy and milk consumption is rare in large parts of Asia and Africa. I drink milk daily because my mother made me drink a glass of milk with breakfast every morning and I fear that I am too old to break that habit now. Milk is a good source of calcium (and in Canada of Vitamin A and D because it is added to milk by the government to prevent deficiency). However, these vitamins and minerals aren’t going to be affected by temperature changes and so pasteurizing the milk will have no effect. Most expert organizations agree that apart from a change in the flavour, there is little nutritional difference between raw and pasteurized milk. Raw milk enthusiasts make a number of other claims that raw milk will boost your immune system. Believe me when I say that if there were a way to “boost your immune system” we would be giving it to chemotherapy patients and those with HIV rather than wasting our time with this debate. The argument centers on the fact that raw milk contains leucocytes and other immune components that will help your immune system. Leucocytes, a.k.a. white blood cells, are the cells that fight off infection. Unfortunately, any leucocytes in milk came from the cow, and a cow’s leucocytes won’t do you any good. In fact they could theoretically do some harm because a cow’s leucocytes see your cells as foreign and would attack them (a concept in medicine we see in transplant patients called graft-versus-host disease). However, in the concentrations observed, they are unlikely to do much any good or harm.
It is possible to drink raw milk and not die in the same way that you can eat raw meat (steak tartar) and not die. But steak tartar is meticulously handled and carefully prepared to minimize the risk of bacterial contamination. However, the risk of infection is not zero and is not recommended for pregnant women or those with compromised immune systems. Sushi is also made of raw fish, but it too is carefully prepared and (in Canada at least) must be flash frozen prior to serving to kill off any bacteria. However, all this preparation incurs some cost which is why these products are somewhat more expensive and only served at fairly high end restaurants. Ordering cheap steak tartar at a local diner, much like buying sushi from a gas station, is no deal in the long run.
Raw milk is managed in the same way. The cows are well treated, fed only the best grain, allowed to roam free and generally treated better than we treat most humans. Importantly, they test their cows and milk for tuberculosis, listeria, and other bacteria and throw away anything contaminated. This is of course incredibly wasteful and costly. It also leads to the destruction of perfectly good food that would be fit for consumption if pasteurized. I know we have been blessed with an abundant food supply here in North America but wilfully destroying food seems wasteful to me when you consider how many people have to do without it.
Clearly, the people advocating raw milk will try to capitalize on the growing “natural is better” delusion that grips our society. It’s important to ask anyone that extols the virtue of raw milk if they have any financial interest in its sale, which of course they always do. So when it comes to raw milk, remember why we started pasteurizing it in the first place because if we forget our history we will be doomed to repeat it.