The BBC has a story on the weird science inside the wonderful world of cheese:
But you don’t have be a connoisseur to appreciate these living castles of microorganisms. Each one is a house that bacteria and fungi built, and each has its own distinctive architectural style according the tastes of its inhabitants.
The bacterial building begins by mixing milk with lactobacillus or streptococcus to turn it acidic. An added enzyme then snips the tails off the milk proteins. Without their tails, the proteins literally fall out of the milk in solid clumps, grabbing globules of fat as they go. Cheesemakers strain out these clumps, or curds, and press them to prepare a cheese for aging.
It’s during this aging that other microbes can start applying their own distinctive character. Take, for instance, Roquefort, a blue cheese dotted with tiny teal crevices. The builder here is Penicillium roqueforti, a fungus that lives naturally in French caves where true Roquefort cheese is aged, though cheesemakers around the world can add it to fresh cheese themselves to get a similar effect.