Question

How do potassium sorbate and benzoate kill yeasts and molds? Would they impart an off-flavor in food?

Answer 1

Potassium sorbate is the potassium salt of sorbic acid, and is much more soluble in water than the acid. Potassium sorbate will produce sorbic acid once it is dissolved in water and is the most widely used food preservative in the world. It is effective up to pH 6.5 but effectiveness increases as the pH decreases. Potassium sorbate has about 74% of the antimicrobial activity of the sorbic acid, thus requiring higher concentrations to obtain the same results that pure sorbic acid provides. Potassium sorbate is effective against yeasts, molds, and select bacteria, and is widely used at 0.025 to 0.10 % levels in cheeses, dips, yogurt, sour cream, bread, cakes, pies and fillings, baking mixes, doughs, icings, fudges.

Though sodium benzoate and benzoic acid have long been used as preservative in foods, but with respect to their narrow pH range in which they are effective and the off-flavor.They impart to the foods they are to preserve, and their toxicological properties compared to some other preservatives.