potassium sorbate is one kind of unsaturated fatty acid compounds. It can be absorbed by human body rapidly, then decomposed into CO2 and H2O, moreover no remaining in body.

ADI 0-25mg/kg (based on sorbic acid FAO/WHO 1994)
LD50 4920mg/kg (large mouse by mouth)
GRAS (FDA, 182.3640 1994)

Its toxicity only 1/12 times table salts and 1/40 times sodium benzoate

It is used for food, cosmetic, medical health product and anti-mortify for tobacco. As unsaturated acid, it also used as resin, aromatics and rubber industry.