Specific bacteria digest proteins and make amino acids and a waste product called Volatile Sulphur Compounds. There are three main Volatile Sulphur compounds; Hydrogen Sulphide, Methyl Mercaptan, and Hydrogen Disulphide. Food industry uses additive containing sulphur to preserve processed foods and beverages. You may recognize some of these names: Inorganic sulfur, as sulfites, sulfur dioxide, bisulfate, or metabisulfite. Sulfur gases smell like rotten eggs.