Potassium bisulfite is a chemical compound with the chemical formula KHSO3. Potassium bisulphite is used for the preservation of colourless food materials such as fruit juices, squashes, apples and raw mango chutney. Potassium bisulfite solutions are used in a variety of different applications, including use as a food preservative (E228) to prevent spoilage and discoloration, as a preservative for pharmaceuticals (nebulizer solutions, parenterals, peritoneal dialysis solutions). It is also an antiseptic and sulfurous acid source, especially in brewing. Potassium bisulfite also functions as hair-waving/straightening agent. Potassium bisulfite is generally recognized as safe by FDA when used in accordance with good manufacturing or feeding practice, except that it is not used in meats or in food recognized as source of vitamin B1.