A synthetic preservative used in amounts of 0.6% or less where it’s proven to be safe and effective. Dehydroacetic acid is characterized as a white to cream crystalline powder. Sometimes its salt form (known as sodium dehydroacetate) is used, as it is more soluble in certain types of cosmetic formulas. Dehydroacetic acid is most effective on fungi.
Reference for this information:
Journal of the American College of Toxicology, 1985, pages 123-159