ABSTRACT
The weak organic acids (e.g., acetic, lactic, and propionic acid, etc.) and their anionic salts (e.g., sodium acetate, potassium lactate, etc.) have been widely used in the preservation of multiple types of human foods for many decades in the U.S. and around the world. In the U.S. many protonated acids and acid salts are identified as generally recognized as safe (GRAS), with no limits on use concentrations other than in accordance with current good manufacturing practices (cGMPs) and to not exceed the content needed for intended effect(s). The organic acids function to inhibit microbial growth primarily through cellular acidification following proton dissociation in a pKa-dependent manner, resulting in metabolic regulation uncoupling. Thus, weak organic acids tend to exhibit greatest antimicrobial activity in foods with reduced pH/elevated acidity. Other reported mechanisms include cellular accumulation of the acid anion, water activity (aw) reduction (particularly for acid salts of organic acids), nutrient uptake inhibition, and membrane permeabilization. Toxicological effects have been reported for multiple organic acids upon excessive acute exposures via inhalational or ingestion-related routes, though multiple researchers and regulatory bodies have identified no toxicological impacts when consumed in foods at standard, approved concentrations.
