Detection of indicator bacteria is one of the best
ways to evaluate the effectiveness of water disinfection
methods. The most important indicator bacteria, in terms
of their importance, include E. coli, coliforms and other
thermotolerant coliforms. The presence of these bacteria
in the water is an indicator of insufficient disinfection
process and also recent and frequent contamination of
water with human and animal feces[4]. Thermo tolerant
coliforms, except E. coli, can enter the drinking water
through water contaminated by industrial wastewaters
and under deterioration soil and water. Conventional
methods for the detection of microbial contamination
of water include methods which are based on culture of
water sample and diagnosis of β-galactosidase (using
ortho-nitrophenyl-β-D-galactopyranoside) which is
cumbersome,expensive and often with personnel error in
routine use[5].