Alkaline peptone water is used for the enrichment of vibrio species in compliance with BIS specification IS 5887 (Part 5) 1976, reaffirmed 1986.

Summary and Explanation

Alkaline peptone water is used for the enrichment of vibrio cholera and vibrio species from food, water feces and clinical studies. This medium has been recommended by OMS, APHA(1) and various authors to increase the recovery of vibrio species in fecal material and other samples. The enrichment in liquid is necessary for isolation of vibrio from feces for the control of carriers and for the examination of drinks, food or sewage. The high values of slows down the development of common contaminants, so that after 6-7 hours of incubation, vibrio, if present, stand out on microscopical examination in dark field.

Principles of the Procedure

Alkaline peptone water is pre-enrichment for vibrio species. Vibrio should be inoculated into an enrichment medium prior to plating onto a selective medium. Alkaline peptone water is a suitable enrichment broth for the enrichment of vibrio species.(2-4) High pH of the medium (6,4) provides a suitable environment for the growth of vibrios. Peptic digest of animal tissue provides nitrogenous, carbonaceous, and other important nutrients. Sodium chloride maintains osmotic equilibrium. The high pH, promotes the growth of vibrio species and suppresses the growth of microbial flora.