What is raw milk cheese?
Simply, it is any cheese made from unpasteurized milk. There are thousands of raw milk cheeses around the world. It's considered to be the "traditional" way of making cheese. Raw milk cheeses are typically more complex in flavor and more tender in texture. In other words, they are REALLY yummy - and they taste like the place from where they came.
What is pasteurization?
Pasteurization when we heat milk to a certain temperature for a period of time in order to eliminate potentially harmful bacteria and extend shelf life.
So why don't we want to do that?
Cheese consists of two main components: milk solids and bacteria. It's the bacteria that give cheese flavor, texture, and aroma. It's also the bacteria that help it age properly without "going bad." Pasteurization kills these "good" bacteria along with the bad, eliminating the natural characteristics they exhibit and making your cheese a little less "terroir" and a little more "meh." High-heat pasteurization can also give cheese a rubbery texture, as it damages the delicate cellular structure.
There ought to be a law...
Well, of course, there is. In the United States, any raw milk cheese must be aged for 60 days before being sold to consumers. This is why you see almost no squishy raw milk cheeses in the US. By the time a cheese is aged for two months, it will be fairly firm.