Sorbate (sorbic acid) generally is an effective inhibitor of most molds and yeasts and some bacteria. Environmental factors such as pH, water activity, temperature, atmosphere, microbial load, microbial flora and certain food components can influence the effectiveness of sorbate. Strains of microorganisms resistant to sorbate exist and therefore are common causes of food spoilage. Some molds and bacteria are able to degrade sorbate. This paper reviews the factors that affect the antimicrobial effectiveness of sorbate in foods.