Peptone Water with Phenol Red, 5 kg

Peptone Water is particularly suitable as a substrate in the study of indole production. Peptic digest of animal tissue used in Peptone Water is rich in tryptophan content. Peptone Water is also utilized as a base for carbohydrate fermentation studies with the addition of sugar and indicators such as bromocresol purple, phenol red or bromothymol blue. Peptone Water with Phenol Red is recommended (1, 2, 3) for studying the ability of an organism to ferment a specific carbohydrate which aid in differentiation of genera and species. The formulation of Peptone Water makes it useful for cultivating non-fastidious organisms (1). This medium is recommended to study fermentation reactions of Yersinia enterocolitica . Peptone Water with pH adjusted to 8.4 is suitable for the cultivation and enrichment of Vibrio species. Peptic digest of animal tissue provides essential nutrients. Sodium chloride maintains the osmotic balance of the medium. Fermentation ability of microorganisms is studied by addition of carbohydrates separately to the basal medium before or after sterilization, such as saccharose, rhamnose, salicin, glucose, dextrose etc. at a concentration of 0.5%. Most of the end products of carbohydrate fermentation are organic acids, which, in the presence of phenol red, show a colour change of the medium from red to yellow. If desired, Durhams tube may be used to detect the gas production if produced. The addition of some sugars can lower the pH of the medium. That can be adjusted with sterile 0.1 N NaOH. Storage and Shelf-life: Store below 30°C in tightly closed container and the prepared medium at 2 - 8°C. Use before expiry date on the label. References: 1. MacFaddin J. F., 1985, Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Vol. 1, Williams and Wilkins, Baltimore. 2. Finegold S. M. and Baron E. J., 1986, Bailey and Scotts Diagnostic Microbiology, 7th Ed., The C.V. Mosby Co., St. Louis. 3. Murray P. R., Baron J. H., Pfaller M. A., Jorgensen J. H. and Yolken R. H., (Eds.), 2003, Manual of Clinical Microbiology, 8th Ed., American Society for Microbiology, Washington, D.C.