Action of Acetic Acid on Food Spoilage Microörganisms

Abstract

This investigation was initiated with the purpose of studying the effect of acetic acid on certain microorganisms related to food spoilage with the hope of securing results of practical value. The main reasons for the use of acetic acid as a food preservative are its toxicity value, commercial availability, and low cost. The toxic effect on microorganisms of an increased hydrogen-ion concentration in the substrate is well established. Acetic acid and certain other organic acids appear to have a toxicity in excess of that which could possibly be due to the pH alone. The consensus of authorities seems to favor the theory that it is the undissociated molecule which is toxic. Kahlenberg and True (1896) found that the undissociated acetic acid molecule was toxic. Winslow and Lockridge (1906) found that acetic and benzoic acids were fatal to typhoid and colon bacilli at a strength at which these acids were but slightly dissociated. Wolf and Shunk (1921) concluded that the hydrogen-ions alone were not responsible for the toxicity of acetic acid. Bach (1932) states that at an interval where the pH has no importance, the undis-sociated part of the lactic acid is the active factor, although generally the hydrogen-ions control the antiseptic effect. In another paper (1932a) the same investigator suggested that the antiseptic action of formic, acetic, propionic, and butyric acids was connected with their influence on surface tension. Foster (1920) also contributed to the idea that the toxic effect was due to the