1.1 ,This test method describes a membrane filter (MF) procedure for the detection and enumeration of Escherichia coli, a bacterium found exclusively in the feces of humans and other warm-blooded animals. The presence of these microorganisms in water is an indication of fecal pollution and the possible presence of enteric pathogens. These bacteria are found in water and wastewater in a wide range of densities. The detection limit of this procedure is one colony forming unit (CFU) per volume filtered.