Tetrasodium diphosphate is a sodium salt of diphosphoric acid used as a food additive, designated E450(iii) in Europe. Like other diphosphates, it acts as an emulsifier, stabiliser, and raising agent: in processed cheese it keeps fats and proteins blended; in baked goods it works with bicarbonate as part of leavening systems; in cured meats it improves water retention and texture. Phosphates are also used to prevent the discoloration of potatoes and to stabilise canned seafood. Intakes are regulated because excessive phosphate can disturb calcium balance, though normal dietary levels from additives are considered safe. It must be declared on ingredient lists by name or E number.