 Total coliforms were used as fecal indicators by public agencies in the US as early as the 1920s.These organisms can be identified based on the fact that they all metabolize the sugar lactose, producing both acid and gas as byproducts.Fecal coliforms are more useful as indicators in recreational waters than total coliforms which include species that are naturally found in plants and soil; however, there are even some species of fecal coliforms that do not have a fecal origin, such as "Klebsiella pneumoniae".