Since I just touched on chickens and eggs, I thought I might touch on milk, too. Both eggs and milk have something in common: they are both highly nutritive: they provide a lot of good stuff to things that eat them. Think about it; an egg yolk is the food source for 30 days for a growing chick. Milk is a food source for a growing mammal for it's first few weeks or months (in some cases, even, years) of life. They need to be very complete foods to the critters that grow on them. Needless to say, you and I are not little chicks, goats, sheep, or cows, so these foods are not "perfect" foods for us. I intend to show a nutritional breakdown of eggs and different kinds of milks in another blog.
There are, however, other things that like to eat milk, too. Which is lucky for us, really; because these little things are bacteria! There's a dozen or so bacteria that live in or are introduced into milk by cheese-makers. The bacteria that live in the milk are the same sorts of bacteria that live in human milk; the lactobacillus acidophilus, and a few others. These bacteria are the "active cultures" in the Activia and other yogurts that are eaten for their recognized heath benefits. These bacteria are also what cause the milk to so delightfully sour into some of our favorite foods. How do they do this? Well, in the right conditions, the bacteria eat the milk and turn it into lactic acid, which gives us the characteristic flavor of plain yogurt. The other bacteria that are added by cheese-makers, and the amount of time the bacteria is allowed to grow, tweak that flavor of the cheese being made into all the recognizable flavors of cheese. There's more to this, of course, there are other enzymes and acids (like vinegar) that are added, and amounts of whey squeezed out of the curds, time of aging and such that further define a cheese to it's finished state. But, that's basically all there is to good, fresh, cheese. Just a little heat, bacteria, and acid or rennet, some draining, and you have fresh, soft cheese!
Sadly, not all bacteria found in milk is "good." Indeed, the reason milk was pasteurized as a standard in this country is because of nastier things that can be found in milk; many of which have been stamped out or can be largely avoided. There used to be a very high number of cases with cows that had Tuberculosis and Brucellosis, both of which can be transmitted to humans. These diseases, thankfully, are no longer as wide-spread, and animals with these diseases are not (or should not be) allowed to contribute to the milk that is being sold. Many of the other bacteria that are still a problem are due only to unsanitary practices. (Read between the lines: poo traces in the milk.) While it is true that any milk exposed to air can be found to contain these bacteria, such as e. coli and coliform, they can be found with greater concentration on your toothbrush or shower head than in your cleanly produced milk--weather it is raw or not.
So what does this mean? Is it or is it not safe to drink milk at all? Does it matter if it is raw or pasteurized? Yes, and yes; although the why's may surprise you. It is safe to drink milk, as long as you know that the source of the milk is a reliably good one, you know the risks involved, and if it is properly handled at all times--even by the consumer. When milk is pasteurized, many things happen. Not only is all good and bad bacteria and the enzymes that promote the rancidification of milk destroyed, but fragile vitamins and proteins are altered or destroyed, as well. If there were to be introduced, via the air in your home or the packaging plant or a grubby finger, a coliform or e. coli bacteria, your only protection against massive multiplication of these nasties in your milk is keeping it cold. Like 45 degrees F or below at all times. What about raw milk, then? Actually, raw milk is already colonized by all of those good bacteria and so it's almost a living immune system. As long as the good bacteria remain the majority they will generally starve out the bad ones. You still have to be careful, though. Most of the good bacteria are more delicate than the bad ones. They can be easily killed out by trace antibiotics in the milk and they don't grow well when it's too cold, either. Indeed, when we make cheese, the good bacteria don't grow well until the milk is around body temperature--96-98 degrees F (as the milk would have been in the body), and the bad bacteria can grow well in cooler temperatures. So you have a choice here; you can keep raw milk cold, too, (45 degrees or below, again) or, you can let it be really warm (a nice 97 degrees or so) which will begin/continue the the cheese-making process inherent in the raw milk itself.
Okay, really, what does all that mean? As far as bacteria go, if the farmer and packager and shipper and then you keep your milk cold and clean, then either milk is suitable for safe drinking. Although, many states have strict laws about the selling of raw milk, and you should always check those. But which is better to drink? That's a topic for the next blog.
Sources of info
Pasteurizing at home: http://www.motherearthnews.com/Real-Food/1998-08-01/How-To-Pasteurize-At-Home.aspx
Raw versus Pasteurized: http://www.realmilk.com/rawvpasteur.html
Why does milk sour: http://www.madsci.org/posts/archives/1999-06/927816857.Ag.r.html
Milk Quality Terms: http://drinc.ucdavis.edu/dairyp/dairyp6.htm
Raw Milk and E. Coli: http://www.megnut.com/2006/09/raw-milk-and-e-coli.html
Why Raw Milk is Becoming More Popular: http://articles.mercola.com/sites/articles/archive/2004/04/24/raw-milk.aspx
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