Sodium triphosphate, also sodium tripolyphosphate, or tripolyphosphate, is an inorganic compound with formula Na PO. It is the sodium salt of the polyphosphate penta-anion, which is the conjugate base of triphosphoric acid.
STPP is used as a preservative for poultry, meat, and seafood. It is also added, along with other sodium polyphosphates, to processed cheeses as an emulsifier. The polyphosphates are negatively charged chains of phosphorus and oxygen that attract water molecules.