So I was looking at a carton of milk in the fridge the other day, (like you do…) and inadvertently reading the word that I’ve seen probably a million times (ok maybe not that many) “Pasteurized.” It occurred to me: what does that even mean? I think we assume that it’s a good and natural part of how we get our milk, but why? I figured I’d try to do some research and figure that out.

Pasturization is a process developed by Louis Pasteur which uses heat to destroy human pathogens. According to the International Dairy Food Association, “‘pasteurized’ and similar terms shall mean the process of heating every particle of milk or milk product, in properly designed and operated equipment, to one (1) of the temperatures” specified by a supplied chart. There are 3 different types of pasteurization: 1) Vat Pasteurization (145F for 30 minutes), 2) High Temperature, Short Time (HTST)  (161F for 15 seconds), 3) Higher Heat, Shorter Time (HHST) which can be a range of times and temperatures from 191F for 1 second up to 212F for 0.01 seconds and, finally, 4) Ultra-Pasteurized (280F for 2 seconds). Fascinating, no?

There also exists one final form, UHT or Ultra-High Temperature which involves heating and packaging the milk in a sterile environment, so it doesn’t require refrigeration. I remember seeing this in Thailand and a few places in Europe. It always weirds me out to see milk that doesn’t require refrigeration.

Now let’s look at the other side of the story: Raw Milk. The term “raw” is actually a bit misleading in my opinion. It seems to imply that milk is somehow normally served “cooked.” Raw milk is simply milk straight out of the cow, minus the pasteurizing. Despite this being it’s natural state, it’s illegal to sell raw milk across state lines and to sell at all in a number of states. Check this map for details. Sounds sinister doesn’t it? Well in doing some research, it’s actually more complicated than that. In fact, what did we do before Louis invented it? Seems unlikely that we just suffered with the occasional death from drinking milk.

There are certainly some marked bad effects of raw milk, the CDC reported 1,007 illnesses, 104 hospitalizations, and two deaths from 45 outbreaks between 1998 to 2005. Yet, compare that to these numbers from the CDC: foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. Suddenly the effects of raw milk are not so impressive. However, they’re not negligible. It does appear from doing some research here and here that it’s likely that these problems with raw milk are likely due to corn feeding the dairy cows. This is known to cause abnormal pH levels in the cow’s internals, creating an environment which breeds pathogens. This explains the need for pasteurization in most of our milk. It also explains what we did pre-pasteurization: we didn’t feed our cows crap. Here’s a neat write-up of that history.

This could be a topic for a future post, but in doing this research it seems to me that grass-fed raw milk may, in fact, be quite healthy.  My local Trader Joe’s and Whole Foods don’t carry any raw milk however, so I guess I’ll be left just wondering about it. If any of you know where I can get some grass-fed whole milk in LA, let me know.

So the short version: pasteurization is a very effective work-around process for dealing with the screw-up of feeding corn and other unnatural food to our cows.