Amperometric quantification of total coliforms and specific detection of Escherichia coli.

The quantitative determination of total and fecal coliforms, as indicators of fecal pollution, is essential for water quality control. We developed a sensitive, inexpensive amperometric enzyme biosensor based on the electrochemical detection of beta-galactosidase activity, using p-amino-phenyl-beta-D-galactopyranoside as substrate, for determining the density of coliforms, represented by Escherichia coli and Klebsiella pneumoniae. The specific detection of E.