The dairy industry is the traditional user of enzymes for the production and improvement of cheese, yogurt, and other milk products. Enzymes have been used for cheese production since 5000 B.C. Enzymes are natural proteins that act as a biocatalyst to cause the desired reaction. Enzymes have a specific function. In the dairy industry, enzymes are used for a range of functions from coagulants to cheese ripening, to improve the solubility and taste of dairy products, and application of bioprotective enzymes to increase the shelf life and safety of products.

The most popular dairy enzyme preparation is rennet which clots milk by removing a highly charged peptide fragment from kappa-casein on the surface of micellar casein, a major form of milk protein. Destabilized casein micelles aggregate and form the structure of the milk clot, which is then acidified by lactic cultures to make cheese curd. Apart from using milk-clotting enzymes to make cheese, the dairy industry processes also make use of non-coagulant proteases, lipases, aminopeptidases, carboxypeptidases, lysozyme, lactase, and lactoperoxidase for various applications including debittering and flavour generation in protein hydrolysates as well as the production of enzyme-mediated cheeses.