Blue cheese is a type of cheese known for its distinct blue or green veins, which are created by the mold Penicillium roqueforti. This cheese has a strong flavor and creamy texture, making it popular in salads, dressings, and as a topping for various dishes. The production of blue cheese involves inoculating the cheese with mold spores during the aging process. It is typically made from cow's, goat's, or sheep's milk. Different varieties of blue cheese, such as Roquefort, Gorgonzola, and Stilton, each have unique flavors and characteristics based on their ingredients and aging methods.