The following may all be added to the cheese milk:
- Calcium chloride
- hydrogen peroxide
Calcium chloride is added to replace calcium redistributed during pasteurization. Milk coagulation by rennet during cheese making requires an optimum balance among ionic calcium and both soluble insoluble calcium phosphate salts. Because calcium phosphates have reverse solubility with respect to temperature, the heat treatment from pasteurization causes the equilibrium to shift towards insoluble forms and depletes both soluble calcium phosphates and ionic calcium. Near normal equilibrium is restored during 24 - 48 hours of cold storage, but cheese makers can't wait that long, so CaCl2 is added to restore ionic calcium and improve rennetability. The calcium assists in coagulation and reduces the amount of rennet required.
Sodium or potassium nitrate is added to the milk to control the undesirable effects of Clostridium tyrobutyricum in cheeses such as Edam, Gouda, and Swiss.
Because milk colour varies from season to season, colour may added to standardize the colour of the cheese throughout the year. Annato, Beta-carotene, and paprika are used.
The addition of hydrogen peroxide is sometimes used as an alternative treatment for full pasteurization.
Lipases, normally present in raw milk, are inactivated during pasteurization. The addition of kid goat lipases are common to ensure proper flavour development through fat hydrolysis.