calcium are lost in the whey, and the
remainder forms a weak, brittle curd. By
contrast, rennet leaves the micelles mostly
intact and causes each to bond to several
others into a firm, elastic curd. Second, the
acidity required to curdle casein is so high
that flavor-producing enzymes in the cheese
work very slowly or not at all.
Cheese Microbes Cheeses are decomposed
and recomposed by a colorful cast of
microbes, perhaps a handful in most modern
cheeses made with purified cultures, but
dozens in some traditional cheeses made with
a portion of the previous batch’s starter.
Starter Bacteria First there are the lactic acid
bacteria that initially acidify the milk, persist
in the drained curd, and generate much of the
flavor during the ripening of many semihard
and hard cheeses, including Cheddar, Gouda,
and Parmesan. The numbers of live starter
bacteria in the curd often drop drastically