According to Mohapatra (488), coliform is a general term used to refer to Gram-negative, rod-shaped facultative anaerobic bacteria. These coliforms are identified by production of a gas from glucose or other sugars. In addition, the fermentation of lactose acid and production of a gas within 48 hours at 35 degrees Celsius is also another identification criterion that is used. Species that fall under the coliform group include Citrobacter, Escherichia (E.coli), Klebsiella and Entrobacter (Mohapatra 488).
Fecal coliform bacteria normally thrive in the intestinal tract of humans and other warm-blooded animals. Hagedorn, Blanch, and Harwood (454), classify fecal coliforms as