Sodium bisulfite

Sodium bisulfite (CAS 7631-90-5), also sold as sodium bisulphite and designated E222 in food applications, is an inorganic sulfite salt used commercially as a reducing agent, preservative, and oxygen scavenger across multiple industries. SBS delivers reliable antioxidant and antimicrobial action at relatively low use concentrations, making it a cost-effective functional ingredient for formulators and process engineers in various sectors.

In food and beverage production, E222 prevents oxidative browning and microbial spoilage in fruit products, wines, dried foods, and seafood processing. Water treatment operations rely on sodium bisulfite to dechlorinate potable water. It is used for treating boiler feedwater, neutralizing residual chlorine before downstream processing or discharge. Textile and paper manufacturers apply it as a bleaching and reducing agent for pulp brightening and dye stripping.

In pharmaceutical manufacturing, it functions as an antioxidant stabilizer in injectable formulations and oral liquid preparations where oxygen-sensitive active ingredients require protection from degradation. Sodium bisulfite is supplied as a white to off-white crystalline powder or granules, with liquid solution forms also available for industrial water treatment applications. Standard commercial grades include food-grade material.

These grades are FCC and E222-compliant, with purity levels typically ranging from 58% to 65% active SO₂ equivalent. Pharmaceutical-grade material meeting USP or Ph.Eur. specifications is also available. These high-purity options are specifically designed for regulated manufacturing environments. The material remains a versatile chemical essential for maintaining product stability and process efficiency globally.