Sodium benzoate
 (Sodium Benzoate) Molecular formula: CH COONa is the sodium salt of benzoic acid, benzoin odorless or slight odor in the acidic food can be converted to the active part of benzoic acid, benzoic acid with anti-corrosion mechanism. As more water soluble than benzoic acid, and stable in air, the role of yeasts and bacteria strong, so more often than benzoic acid. Toxicological basis: LD oral rat 4070 mg. kg -1 (bw) 50GRAS FDA-21CFR 184.23,181.733 ADI 0-5 mg. kg -1 (bw) (the total amount of formic acid and its salts, benzoic acid count) (FAO / WHO, 1994)

 Corrosion mechanism
 Benzoic acid preservatives is not dissociation of its molecules play a role, not the acid dissociation lipophilic, easy through the cell membrane into the cell, fungi and bacteria and other microorganisms interfere with cell membrane permeability, hinder the cell membrane of the amino acid absorbed into the cells of the acid molecules, acidification of intracellular storage base, inhibit respiratory enzymes within the microbial cell activity, and thus play a role in anti-corrosion (HOU Zhen Jian, 2004). Benzoic acid is a broad-spectrum anti-microbial agents, the yeast, fungi, bacteria, effect of some good use within the allowed maximum, at pH 4.5 and below, a variety of bacteria are inhibited.