Sulphur  dioxide, bisulphites  and  sulphites:  Sulphites, as  a source  of sulphur dioxide, has been extensively used  as preservatives in foods for quite sometime now. They are effective, versatile and economical  additives which are used  as antimicrobials  in  the preservation of a number  of  food  items  viz. jam,  jelly, marmalade, hit,  hit  pulp and juices,  syrups and sherbets, alcoholic beverages, confectionery,  dry  hits and meat products.  They  are also used as bleaching agents in the refining of sugar as antimicrobial agents, to control enzymatic and non-enzymatic browning reactions  in dehydrated  hits and  vegetables and  to provide protection against oxidative reactions.