Sodium tripolyphosphate (STPP), also known as sodium triphosphate, is the sodium salt of triphosphoric acid. ... As a food additive, STPP helps with moisture retention and is used to preserve the natural color of meat and fish products while improving their texture. STPP is a preservative for seafood, meats, poultry, and animal feeds. It is common in food production. , STPP is used as an emulsifier ...