Standard Nutrient Broth No. 1

Composition**

Final pH (at 25°C): 7.5±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 25 grams in 1000 ml distilled water. Heat if necessary to dissolve the medium completely. Dispense and sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes.

Principle And Interpretation

Nutrient media are basic culture media used for maintaining microorganisms (1), for purity checking prior to biochemical or serological testing. The Peptone special, incorporated in this broth is an enzymatic protein digest of animal tissue especially adapted for the preparation of media for culturing fastidious bacteria. The peptone and yeast extract provides nitrogenous compounds, carbon, sulphur, trace ingredients. Sodium chloride maintains the osmotic equilibrium.

Addition of different biological fluids such as horse or sheep blood, serum, egg yolk etc. makes it suitable for the cultivation of related fastidious organisms (2).

Quality Control

Appearance

Cream to yellow homogeneous free flowing powder

Colour and Clarity of prepared medium

Light amber coloured clear solution in tubes

Reaction

Reaction of 2.5% w/v aqueous solution at 25°C. pH: 7.5±0.2

pH

7.30-7.70

Cultural Response

M1224: Cultural characteristics observed after an incubation at 35-37°C for 18-48 hours.

Cultural Response

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.

Reference

1. Lapage S., Shelton J. and Mitchell T., 1970, Methods in Microbiology, Norris J. and Ribbons D.(Eds.), Vol. 3A., Academic Press, London.
2. MacFaddin J., 1985, Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Vol. I, Williams and Wilkins, Baltimore.