Sorbic Acid

The brief history of Sorbic acid is that it is a natural preservative first isolated in 1859 from the berries of an ash tree. Sorbic acid is unsaturated fatty acid containing two carbon-carbon double bonds and both are in the trans configuration. Investigation of its antimicrobial activity found it to be an effective inhibitor of molds, yeasts, and fungi. Sodium and potassium salts of sorbic acid (i.e., sodium sorbate and potassium sorbate) are not as effective. The free acid form is more effective as an antimicrobial. It should be noted that antimicrobial activity of sorbic acid increases as the pH of the media decreases. Enhanced activity at low pH results from the acid being fully protonated (unionized) and thus readily taken up by the microorganism. Combination of sorbic acid and lactic acid have also been shown to inhibit the growth of the pathogen Salmonella. Sorbic acid is widely used to inhibit yeast and molds in processed cheese, wine, fruit juices, and some baked goods (pastries). It is also used in processed meats as an alternative to preservation using nitrites.