Tryptone Water w/o Sodium Chloride

Composition

Final pH (at 25°C): 7.4±0.1

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 10.0 grams in 1000 ml distilled water. Heat if necessary to dissolve the medium completely. Dispense as desired and sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. For testing Vibrio parahaemolyticus add Sodium chloride to a final concentration of 8 or 10% as desired before sterilization.

Principle And Interpretation

Tryptone Water without Sodium chloride is recommended by BIS (1) for detection of Vibrio chloreae and with addition of 8 to 10% sodium chloride for detection of Vibrio parahaemolyticus. Casein enzymic hydrolysate provides carbonaceous nitrogenous compounds and other essential growth nutrients. When testing for Vibrio parahaemolyticus the test sample is inoculated in the tubes containing sterile 1% Tryptone Water without Sodium chloride and with 8% and 10% Sodium chloride. The tubes are inocubated at 37°C for 24-48 hours. Vibrio parahaemolyticus does not grow in the tubes without Sodium chloride.

Quality Control

Appearance Cream to yellow coloured homogeneous free flowing powder

Colour and Clarity of prepared medium Yellow coloured clear solution without any precipitate.

Reaction Reaction of 1.0% w/v aqueous solution at 25°C. pH : 7.4±0.1

pH 7.30-7.50

Cultural Response Cultural characteristics observed after an incubation at 35 - 37°C for 24 hours.

Storage and Shelf Life

Store below 30°C in tightly closed container and the prepared medium 2-8°C. Use before expiry date on the label.

Reference

1. Bureau of Indian Standards, IS:5887 (Part-V) 1976, reaffirmed 1986.