Potassium sorbate, the potassium salt of sorbic acid, is a commonly used preservative in food with the European food additive number E202. Generally, it is synthetic, vegan and gluten-free.

This ingredient is used to protect food from spoilage and therefore prolong the food shelf life by slowing the growth of molds and yeasts. You may have seen it in the label of wines, cheeses, cider, mead, soft drinks, and baked goods.

http://www.chinafooding.com/Potassium_Sorbate