Table 1.

The various methods developed to detect the presence of coliforms.

Method (Use of specific media/method/chemical)	Principle	References
Use of Robert Koch’s solid gelatin media	Counting bacteria based on colony forming unit	Hutchinson and Ridgway, 1977
Wurtz method	Enumerating B. Coli based on lactose fermentation	Ashbolt et al., 2001
Use of durham’s tubes	Positive identification of coliform based on acid and gas production from lactose fermentation	Durham, 1898
Use of MacConkey’s broth	Coliform identification based on being bile tolerant lactose fermenters	MacConkey, 1905
Most Probable Number	Quantitative test recommended by the World Health Organization. Based on lactose fermentation ability of coliforms forming acid and gas, capability of E. coli to reduce methylene blue to exhibit green metallic sheen on Eosin Methylene Blue agar, competence of coliforms to ferment lactose producing gas in the presence of bile	American Public Health Association (APHA), 1992; Clesceri et al., 1996 Mishra et al., 2012; Mishra et al., 2013
Modified Eijkman test	Quantitative test recommended by the World Health Organization. Based on lactose fermentation knack of strictly fecal coliforms forming acid and gas	WHO, 2011;Mishra et al., 2012, 2013
Membrane filtration	Usage of filters would trap the coliforms which could be counted in terms of CFU on media	World Health Organization [WHO] (1996)
MMO-MUG (Colilert®, Coliscan®, and Colitag®)	Enzyme based detection of E. coli	United States Environmental Protection Agency [USEPA], 2002
ELISA and PCR	Antibody specificity	Yoon and Kim, 2012
Paper based microfluidic diagnostics	Based on catalase test	Yetisen et al., 2013
Biosensors	Chromogenic substrate- enzyme interaction based	Thakur and Ragavan, 2013; Kim and Myung, 2015; Hesari et al., 2016