Essential depot says:
Potassium sorbate, the potassium salt of sorbic acid, is a naturally-occurring organic acid. Potassium sorbate is the most widely used food grade preservative and is not a broad spectrum preservative for cosmetic use. It is used as a mold, bacterial and yeast inhibitor and as a fungistatic agent in foods. It is also used in cosmetics, pharmaceuticals, tobacco and flavoring products. Our food grade potassium sorbate is made up of white to off-white tiny flakes, dissolves instantly in water and has a melting point of 270C. The FDA regards this product as GRAS (generally regarded as safe). Usage level: 0.5% to 1.0%. For making toiletries: Dissolve potassium sorbate in the water phase at the beginning of your process until well dissolved. INCI: Potassium sorbate.