Although coliforms were easy to detect, their association with fecal contamination was questionable because some coliform are found naturally in environmental sample. this led to the introduction of the fecal coliform as an indicator of contamination. Fecal coliform,first defined based on the works of Eijkman is a subset of total coliform that grows and ferments lactose at elevated incubation temperature, hence also referred to as thermotolerant coliforms. fecal colifrome analyses are done at 45.5c for food testing, except for water, shellfish and shellfish harvest water analyses, which use 44.5c. the fecal coliforme group consists mostly of e.coli but some other enterics such as Klebsiella can also ferment lactose at there temperatures and therefore, be considered as fecal coliforms. The inclusion of Klebsiella spp in the working definition of fecal coliforms diminished the correlation of this group with fecal contamination. As a result, e.coli has reemerged as an indicator, partly facilitated by the introduction of newer methods that can rapidly identify e.coli.