A basal medium to study fermentation reactions by adding carbohydrates
ANDRADE PEPTONE WATER (VEG.) is used as a basal medium to study fermentation reactions by adding carbohydrates. Medium contains Veg. Peptone which provides nitrogen and carbon source for the growth of microorganisms. Sodium chloride is added to maintain the osmotic balance. The conditions are ideal to get high resuscitation rates for sub - lethally injured bacteria and intense growth. Andrade indicator is a solution of acid fuchsin which when titrated with sodium hydroxide; changes colour from pink to yellow. The Andrade indicator changes colour from yellow to pink as the pH decreases. The medium is pink when hot but becomes straw coloured on cooling. Test carbohydrate solutions should be sterilized separately and aseptically added to sterile Andrade Peptone Water. The biochemical identification of organisms capable of growing in this medium is made by various sugar fermentation results. Use fresh cultures of organisms only which have been presumptively identified by Gram staining and colony morphology. For final identification further biochemical tests are required. Compare the results with uninoculated test tube.