The maturation of cheese includes all of the chemical changes occurring in the cheese after manufacture. Some alterations begin before the curd making is finished. The structure and composition of the cheese change; hence its organoleptic properties. Biochemical, microbiological, as well as purely chemical and physical aspects are involved. Development of cheese properties, including consistency and flavor, is especially attributable to the conversion of lactose, protein, fat, and, in some cheeses, citrate.