Sorbic acid is an antimicrobial agent, or preservative, commonly added to food. A sorbic acid salt, potassium sorbate, is frequently used as well. Sorbic acid occurs naturally in many plants, according to the Center for Science in the Public Interest, or CSPI. It also is made synthetically. Sorbic acid was originally isolated from berries of the mountain ash tree, according to the Iowa State University Extension. It is an unsaturated fatty acid with a weak acrid odor and acidic taste.

Sorbic acid and its salts are very effective at inhibiting most common microorganisms that cause foods to spoil, according to Food-Info, a website associated with Wageningen University in the Netherlands. These preservatives are primarily effective against certain strains of yeasts and molds, and they work by inhibiting enzymes in microbial cells.

Food manufacturers add sorbic acid and potassium sorbate to a wide variety of products, including bread and other bakery foods, cheese, yogurt, dried fruits, gelatin, jelly, syrup, sauces and soft drinks. Sorbic acid and potassium sorbate also are used as wine preservatives, according to the Iowa State University Extension. Sorbic acid has other uses in addition to preserving foods and beverages, notes Reciprocal Net. Manufacturers of animal feeds, cosmetics, pharmaceutical products and tobacco products also use this substance to protect their items from spoilage.

Sorbic acid and potassium sorbate are very stable at high temperatures, so they can be used in heated foods, according to Food-Info. Sorbic acid and potassium sorbate are safe, versatile and efficient, according to Food-Info. The CSPI classifies sorbic acid as "safe" for use as a food additive. Not everyone agrees that sorbic acid belongs in food, however. Whole Foods Market, for instance, includes sorbic acid and potassium sorbate, as well as another sorbic acid salt, calcium sorbate, on a list of ingredients the company finds unacceptable in food products.