Step Three:

Starter cultures and or enzymes are added to the milk for several reasons. As they reproduce in the milk, they help to acidify it which allows it to coagulate easier. These bacteria produce acid by fermenting lactose into lactic acid. Milk PH is normally 6.5 and when it is lowered to 5.3 the casein micelles lose their negative charge and clump together. These bacterial starter cultures and enzymes also contribute to the ultimate flavor and texture of the resulting cheese.