Phenol Red Lactose Broth

Product Identifier

Composition

**Formula adjusted, standardized to suit performance parameters

Directions:

Suspend 25.02 grams in 1000 ml distilled water. Heat if necessary to dissolve the medium completely. Dispense in tubes with inverted Durhams tubes. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes.

Principle And Interpretation

Lactose fermentation is a characteristic that is of great practical importance in the primary isolation of pathogenic enterobacteria. This single characteristic makes possible an immediate presumptive distinction between the intestinal commensals of various genera which ferment lactose and those of the intestinal pathogens i.e. Salmonella, Shigella, which do not ferment lactose (1). Phenol Red Lactose Broth is formulated as recommended by ISO Committee (2) for studying lactose fermentation by coliforms, which is an important differentiating characteristic for the members of Enterobacteriaceae (3).

Peptic digest of animal tissue provides nitrogenous compounds and other essential growth nutrients. Phenol red is the pH indicator, which turns yellow in acidic condition. 18-24 hours old pure culture is inoculated and incubated at 35 to 37°C for 18-24 hours or upto 30 hours).

Type of specimen

Water samples

Specimen Collection and Handling:

For water samples, follow appropriate techniques for sample collection, processing as per guidelines and local standards (2). After use, contaminated materials must be sterilized by autoclaving before discarding.

Warning and Precautions :

Read the label before opening the container. Wear protective gloves/protective clothing/eye protection/face protection. Follow good microbiological lab practices while handling specimens and culture. Standard precautions as per established guidelines should be followed while handling specimens. Safety guidelines may be referred to in individual safety data sheets.

Limitations :

1. This media is used confluence with other biochemical test to identify cultures of isolated microorganisms.
2. Further biochemical and serological tests must be carried out for further identification.

Performance and Evaluation

Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at recommended temperature.

Quality Control

Cultural Response

Key: (*) Corresponding WDCM numbers.

(#) Formerly known as Enterobacter aerogenes $ Formerly known as Proteus vulgaris

Storage and Shelf Life

Store between 10-30°C in a tightly closed container and the prepared medium at 15-25°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle in order to prevent lump formation due to the hygroscopic nature of the product. Improper storage of the product may lead to lump formation. Store in dry ventilated area protected from extremes of temperature and sources of ignition. Seal the container tightly after use. Product performance is best if used within stated expiry period.

Disposal

User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow established laboratory procedures in disposing of infectious materials and material that comes into contact with sample must be decontaminated and disposed of in accordance with current laboratory techniques (5,6).