Also known as sodium hydrogen sulfite, is an antioxidant, used as food preservative, preserves freshness and color in vegetables and juices.
Sodium bisulfite releases sulfur dioxide gas (which is harmful if inhaled) when added to ice, acid or water, killing yeast, fungus, and bacteria. It kills microbes and in fruit canning prevents browning. Used in wine making to prevent oxidation and preserve flavor.
Warning: Not be used in concentrations exceeding 1.25% by weight or heat over 300F.