General purpose growth medium & as the base of carbohydrate fermentation media. It is recommended by BIS committee under specification IS:5887 (Part I) 1976, reaffirmed 2005. PEPTONE WATER (as per BIS) is used for general purpose growth medium & as the base of carbohydrate fermentation media. Peptone Water is recommended by BIS for detection of Indole production by Escherichia coli. Peptic digest of animal tissue provides essential nutrients. Sodium chloride maintains the osmotic balance. To detect indole production add 0.5 ml of Kovacs reagent to the tube and shake the tube gently. Appearance of a red colour indicates presence of indole.