Milk 101

Posted by on Sep 2, 2011 | 0 comments

Am I the only one, or does anyone else find the task of choosing your milk from the infinite number of products out there these days–all boasting different qualities and health benefits–to be a daunting task? Sometimes I would catch myself standing in front of the dairy case motionless, for minutes at a time, contemplating whether or not it is more environmentally correct to buy the organic milk from California or the local generic milk, whether is healthier to buy the skim or the whole milk. Do I want my milk fortified with vitamins and fiber? What product is actually the most “natural” or traditionally prepared? And finally, why is essentially all milk, organic or generic, labeled pasteurized and homogenized? Are these procedures related and are they necessary? After some research, both online, and with the help of Anne Mendelson’s informative book Milk, I have come to a few conclusions that have helped me solve my dairy dilemmas.

What I learned is that pasteurization is a completely separate process from homogenization. Pasteurization involves heating milk to at least 145 degrees F to kill off any pathogens. There are many raw milk advocates in the United States that maintain raw milk from happy and healthy cows is perfectly safe and that pasteurization destroys milk’s taste and healthful qualities. However, the FDA and state health departments have deemed raw milk dangerous, and pasteurization is required in most states. Homogenization, on the other hand, does not affect milk’s safety, and non-homogenized milk is legal in all 50 states. So why is it that virtually all milk sold in the United States is homogenized, and what does this process do to milk?

As a suburban kid far away from any dairy farms, having access to only pasteurized and homogenized milk, I never realized how milk fresh from the cow naturally separates into two layers until I started going to the farmers’ market a few years ago. At the top are the fat globules and the fat-soluble vitamins. At the bottom is the fluid portion of the milk, containing the casein and the protein. When milk is homogenized, the fat globules are crushed into droplets too small to rise to the surface of milk to form a cream layer.

Two breakthroughs in the 1890s – the mechanical separation of cream by centrifuge and the Babcock test to measure the exact fat content of milk – made it possible to create the precise grades of homogenized milk that most people consume today: skim, 1%, 2%, and whole milk. Milk in its natural state cannot be graded in this fashion, because the fat in milk can differ simply between milkings, and because even “skimming” the cream layer off of whole non-homogenized milk always left some residual fat.

These milk-fat categories have helped increase milk sales to a diet-conscious public. But there are several drawbacks to homogenized and reduced fat milks. For one thing, vitamins A, D, E, and K are fat soluble, and therefore we cannot absorb the naturally occurring vitamins in milk by drinking homogenized skim milk. In an effort to compensate for this loss, milk producers normally fortify their milk with vitamins. Also, to give skim milk the appearance of creamy milk, it is often mixed with skim milk powder, which has been said to contain a large amount of oxidized cholesterol. The process of homogenization itself is often regarded as ruining milk’s natural fresh flavor and velvety mouth-feel. Some research has shown that it may also have negative health effects, although clinical studies do not support claims that homogenization contributes to cancer or heart disease.

Homogenization was first invented in 1899, but it was not widely applied to commercial milk for decades. Well before the low-fat diet craze of the 1970s, people used to judge the quality of their milk by the thick layer of cream at the top of their glass bottles, indicating richness and a high butterfat content. That made homogenized milk unappealing at the time. After World War II and the growth of large-scale supermarkets, milk in glass bottles with the visible cream-line was replaced by homogenized milk in convenient throwaway cartons. Soon, consumers seemed to forget about their beloved cream-top milk.

I have decided that, whenever possible, I will choose whole, non-homogenized, pasteurized milk from local farmers because it seems to be the most natural, nutritionally intact, delicious, and legal option in Maryland.

Non-homogenized milk is making a comeback with the resurgence of farmers’ markets and milk delivery programs. I encourage everyone to seek out non-homogenized (and raw if legally available) milk and give it a try. If the idea of whole milk concerns you because you are worried about saturated fats, simply skim your milk the old-fashioned way by buying non-homogenized milk and letting the cream rise to the top over the course of 24 hours in the refrigerator, then use a wide spoon to skim off the cream-layer. You can use that cream for something else, or churn it into delicious homemade butter!