Teepol Medium (without Membrane Filter)

Principle And Interpretation

Field of Application:

Water, food, waste water.

DriFilter Membrane Nutrient Pad Medium is ready to use sterile culture media in the form of a 50 mm biological inert absorbent pads impregnated with Teepol medium, then dried and sterilized in 55 mm petri plate. They eliminate the need of laborious media preparation and autoclaving procedures. The nutrient pads are to be just rewetted with sterile distilled water and are ready to use.

Use of nutrient pads allows larger sample volumes to be tested at a time. Interpretation of results is directly by counting the CFUs and also quantifies the microbial load present in the sample.

The use of teepol in place of bile salts was previously recommended by Jameson and Emberley (1). Burman (2) showed that if a preliminary incubation is carried out at lower temperature resuscitation is not required. Non-chlorinated organisms benefit from 4 hours incubation at 30°C but chlorinated organisms require 6 hours incubation at 25°C.

The coliform and Escherichia coli count are made on separate volumes of water. The yellow colonies formed are further identified.

• Presumptive coliform organisms : Yellow colonies from membranes incubated at 35°C, when subcultured in Lactose Peptone Water produce gas at 35°C after 43 hours.
• Presumptive Escherichia coli: Yellow colonies from membrane at 44°C when subcultured into Lauryl Tryptose Mannitol Broth, incubated at 44°C produce gas and indole after 24 hours.