Lactic Acid

Lactic Acid produced by many kinds of bacteria in the fermentation of milk and of some vegetable products, is mainly responsible for the sour taste of most milk products, and of other products, including sauerkraut, gherkins, olives, and cocoa.

Lactic acid-producing bacteria, often more simply called lactic acid bacteria, change the degree of acidity in (to take the main example) milk. When this process reaches the point at which the proteins are precipitated, the first step in cheese-making has been accomplished; the curd which will eventually become the finished cheese has been formed. The differing characteristics of the various lactic acid bacteria are one important factor in bringing about the wide variety of characteristics in cheeses.