Method 1103.1: Escherichia coli (E. coli) in Water by Membrane Filtration Using Membrane-Thermotolerant Escherichia coli Agar (mTEC), March 2010

摘要

The MF method provides a direct count of bacteria in water based on the development of colonies on the surface of the membrane filter (Reference 18.4). A water sample is filtered through the membrane which retains the bacteria. After filtration, the membrane is placed on a selective and differential medium, mTEC, incubated at 35 degrees C + or = 0.5 degrees C for 2 + or = 0.5 hours to resuscitate injured or stressed bacteria, and then incubated at 44.5 degrees C + or = 0.2 degrees C for 22 + or = 2 hours. Following incubation, the filter is transferred to a filter pad saturated with urea substrate. After 15 minutes, yellow, yellow-green, or yellow-brown colonies are counted with the aid of a fluorescent lamp and a magnifying lens.