Standard Nutrient Broth No. 2

Composition**

Final pH (at 25°C): 7.5±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 15 gms 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

Fastidious organisms are organisms which require preformed organic molecules like vitamins, amino acids, nucleic acids, carbohydrates. In general, bacterial pathogens need more preformed organic molecules than non pathogens. Media which are highly nutritional are generally used to enrich less fastidious organism so as to isolate them from test samples. Standard Nutrient Broth No.2 can also be used for the examination of water (1).

Meat Peptone and Casein enzymic hydrolysate in the medium provides the nitrogenous and carbon source with other essential nutrients. Sodium chloride maintains the osmotic equilibrium of the medium.

Quality Control

Appearance: Cream to yellow homogeneous free flowing powder

Colour and Clarity of prepared medium: Amber to dark amber coloured clear solution in tubes

Reaction: Reaction of 1.5% w/v aqueous solution at 25°C. pH : 7.5±0.2

pH: 7.30-7.70

Cultural Response

M1628: Cultural characteristics observed after an incubation at 35-37°C for 18-48 hours.

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. Din Deutsches Institut fur Normung e.V: Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung, Mikrobiologische Verfahren (Gruppe K). Nachweis von Pseudomonas aeruginosa (K 8). DIN 38411.