The milk is pasteurized to make it safe. The pasteurized milk is then pumped into the cheese maker vat. Lactic bacteria is added to give flavor. Then, an enzyme, rennet is added to the mixture that causes the milk to thicken to the consistency of jello. The next step is to cut the gel like consistency into small curds and eliminate the whey.
Curds are the solids in milk and the whey is a watery by-product.
Cutting and cooking causes the whey to separate from the curds.