SBS

Sodium bisulfite (or sodium bisulphite, sodium hydrogen sulfite) is a chemical mixture with the approximate chemical formula NaHSO₃. Sodium bisulfite in fact is not a real compound, but a mixture of salts that dissolve in water to give solutions composed of sodium and bisulfite  ions. It is a white solid with an odor of sulfur dioxide. Regardless of its ill-defined nature, “sodium bisulfite” is a food additive with E number E222.

Sodium bisulfite is commonly used as a reducing agent in industrial applications. It is also used to remove residual chlorine in both waste water and industrial applications. In the food industry, sodium bisulfite is used as a preservative and as a steeping agent.