Sodium triphosphate [E451] (STP, sometimes STPP or sodium
tripolyphosphate or TPP,) is an inorganic compound with formula Na5P3O10.The
majority of STPP is consumed as a component of commercial detergents. It serves
as a "builder," industrial jargon for a water softener. It is used as
a food additive and often found in instant noodles.
STPP is a preservative for seafood, meats, poultry, and
animal feeds. It is common in food production as E number E451. In foods, STPP
is used to retain moisture. Many governments regulate the quantities allowed in
foods, as it can substantially increase the sale weight of seafood in
particular.
