What is Potassium Benzoate?
Potassium benzoate is the potassium salt of benzoic acid and is used as a food preservative to inhibit the growth of mold, yeast and some bacteria.  Potassium benzoate occurs naturally in many plants and animals. 
Potassium benzoate appears to be safe for most people, though they cause hives, asthma, or other allergic reactions in sensitive individuals. In children, sodium benzoate may adversely affect behavior (especially in children with Attention Deficit-Hyperactivity Disorder).