Skim through

What it does: preservative, product stabiliser 

Also called: potassium salt of sorbic acid

The science

Potassium sorbate is a woman-made preservative and chemical additive. It's widely used as a preservative in foods, drinks, and personal care products. It is an odorless and tasteless salt synthetically produced from sorbic acid and potassium hydroxide.

TLDR

Potassium sorbate is a preservative and it help your cosmetics last longer. It’s not a strong one and doesn’t really work against bacteria, but more against mold and yeast. To do that it has to break down to its active form, sorbic acid. For that to happen, there has to be water in the product and the right pH value (pH 3-4).