Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Potassium benzoate (E212), the potassium salt of benzoic acid, is a food preservative that inhibits the growth of mold, yeast and some bacteria. It works best in low-pH products, below 4.5, where it exists as benzoic acid. Acidic foods and beverages such as fruit juice (citric acid), sparkling drinks (carbonic acid), soft drinks (phosphoric acid), and pickles (vinegar) may be preserved with potassium benzoate. It is approved for use in most countries including Canada, the U.S., and the EU, where it is designated by the E number E212. In the EU, it is not recommended for consumption by children. Potassium benzoate is also used as the whistle in many fireworks. One very common way to make potassium benzoate is by oxidizing toluene. Another way to synthesize potassium benzoate in the lab setting is by reacting methyl benzoate with potassium thioacetate.