Yes, The makers of probiotic yogurts have convinced people to love eating germs, for the health benefits. But what about cheese? Most cheeses are a bacteria ranch that keeps growing and evolving, right until the moment it dissolves in your stomach. How disgusting is cheese-making? Very.
People always say that you don't want to see how the sausage is made — but actually, cheese-making is more disgusting than sausage making. At least once the sausage is made, well, the bad part's over. Sausage makers produce a final product that's free of bacteria. Cheese makers, meanwhile, craft an ongoing bacteria city, that keeps developing on the shelf.
The basic making of cheese is pretty simple. You need enzymes, and you need bacteria.
Traditionally, the enzymes would have come from bile, from the inside of a calf. This bile, or rennet, contained rennin, which curdled the milk that the calf got from its mother. It would go on to curdle the milk that's turned into cheese. The earliest cheese was made with only this, and then preserved with salt. Then the process became dirty. Bacteria drift through the air of pretty much any nation, and they landed in the curds, and started living there. They convert the lactose in milk to lactic acid, subtly changing the flavor the cheese. (If you leave it in for long enough, bacteria will produce enough lactic acid to curdle the milk on their own, which is why milk curdles in the carton. There's no telling which bacteria actually produced that curdling, though, so don't eat those curds.)
And these bacteria pretty much never stop living in the cheese. This is why aged cheese is different from new cheese. As the bacteria go through the lactose in the cheese, converting more and more material, the taste becomes stronger and sharper. The quick process stops when the whey - the sweetish white liquid that the curds sweat, famous for being the favorite food of Miss Muffet - gets drained away. But the bacteria is still in there. Hard cheeses are pressed so much of the liquid goes out of them. Some cheeses, like mozarella, are melted and re-pressed, until they get the right flavor.
Over time, different areas of the world developed different flavors of cheese. It starts with the native bacteria of the region. France, for example, has bacteria that lead to the white, powdery wheels of cheese that the region is so well known for. America is more known for bacteria that produce sharpish hard cheeses. And of course the Swiss have — among others — the bacteria that pump out carbon dioxide, giving the cheese its distinctive holes. Each cheese maker saves some of the last batch of cheese to make a starter, a bacterial sample, that gets the next batch going - like a rancher keeping a stock of laying hens or calving cows to get the next generation. After a while, the best strains of bacteria got sold or passed around, along with techniques that told cheese makers exactly how long to let them grow, when and how much to heat them, and how long to age them for a specific taste.
American-made cheese is generally considered to be limited and sad compared to foreign cheeses for a very simple reason; pasteurization. The USDA requires that cheeses be made with milk that is pasteurized, flash boiled or irradiated, in order to remove any harmful bacteria. If the milk isn't pasteurized, it has to be aged for sixty days before it can be sold to the public. This makes certain flavors in certain fresh cheeses impossible to achieve in America. It's a loss to foodies, but it has a certain historical aesthetic that I, personally, like.
Early cattle and goat herders had to recognize early the nutritious potential of milk. They also had to recognize its dangers. Milk went off quickly, either curdled or colonized by harmful bacteria that would kill the human who drank it. Hence, those early cheese-making methods that used simple rennet to curdle the milk, or stronger acids to curdle it before the bacteria could get the chance. This was all designed to let them enjoy the milk a little longer.
And then the beneficial bacteria came along. A