Are all cheeses rotten?

Not all cheeses are "rotten." Cheese is made by curdling milk and then aging it for a certain period of time. During this aging process, bacteria or mold can be added to the cheese to give it a distinct flavor and texture. The bacteria or mold can also help preserve the cheese. This is how some types of cheese like blue cheese, Roquefort, Gorgonzola, Camembert and Brie.

However, not all cheeses are made this way. Fresh cheese like mozzarella, ricotta and cottage cheese, do not rely on mold or bacteria for their flavor or preservation, and are not considered "rotten" cheeses.