Describes cheeses matured with the deliberate growth of moulds that develop their flavour, texture, and appearance. Blue cheeses such as Roquefort, Stilton, and Gorgonzola are pierced to admit air so Penicillium roqueforti veins spread through the paste, creating sharp, piquant flavours. White mould-ripened cheeses like Brie and Camembert grow a bloomy Penicillium camemberti rind that ripens the cheese from outside in, producing creamy texture and mushroomy notes. These are food-safe, selected cultures, entirely different from spoilage moulds. Makers control temperature, humidity, and time precisely, since the same moulds in the wrong conditions would ruin rather than refine the cheese.