The primary ingredient in cheese is milk. Cheese is produced by coagulating the proteins in milk, leading to the separation of curds and whey. Various types of milk may be used, including cow, goat, sheep, and buffalo, each contributing unique flavors and textures to the cheese. The fermentation process is often initiated with the addition of starter cultures and rennet, which helps to form the curds. After curdling, the curds are pressed, salted, and sometimes aged to develop desired characteristics. The diversity in milk sources and production methods results in an extensive variety of cheeses worldwide.