Food preservatives are a type of food additives that prevent food spoilage due to the action of microorganisms and prolong the shelf life of food. Its anti-corrosion mechanism is mainly to reduce the water activity of the product, reduce the PH of the product, act on the specific structural parts of the microorganism, destroy the growth of the microorganism or the normal progress of the metabolic system, thereby inhibiting the growth of the microorganism and prolonging the shelf life of the product.

sodium tripolyphosphate is neutralized by phosphoric acid into sodium orthophosphate by soda ash, and then condensed. There are two methods of producing phosphoric acid, wet method and thermal method.

sodium benzoate is an organic substance with the chemical formula C7H5NaO2. It is a white granular or crystalline powder, odorless or slightly benzoine smelling, slightly sweet, with astringent taste. The relative molecular mass is 144,12. It is air stable and easily soluble.

sodium tripolyphosphate is an inorganic substance with the chemical formula Na5P3O10. It is a kind of amorphous water soluble linear polyphosphate. It is widely used in food as a moisture store, quality enhancer, pH regulator and metal chelating agent.