Benzoic acid preservatives act on their undissociated molecules. Undissociated benzoic acid has strong lipophilicity and is easy to pass through the cell membrane and enter the cell, interfering with the permeability of the cell membrane of microorganisms such as molds and bacteria, and hindering the cell membrane to amino acids. Absorb and enter the benzoic acid molecules in the cell, acidify the alkali storage in the cell, inhibit the activity of the respiratory enzyme system in the microbial cell, and thus play a preservative role.

Benzoic acid is a broad-spectrum antimicrobial agent, which has a good effect on yeast, mold and some bacteria. It has inhibitory effect on various bacteria within the maximum allowable use range and pH value below 4.5.