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Evaluation of C‐EC‐agar, a modified mFC‐agar for the simultaneous enumeration of faecal coliforms and Escherichia coli in water samples
Author(s) -
Jermini M.,
Domeniconi F.,
Jäggli M.
Publication year - 1994
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.1994.tb00468.x
Subject(s) - agar , enumeration , escherichia coli , microbiology and biotechnology , enterobacteriaceae , lactose , biology , fecal coliform , salmonella , food science , incubation , bacteria , coliform bacteria , brilliant green , chromatography , chemistry , biochemistry , water quality , ecology , genetics , mathematics , combinatorics , gene , organic chemistry
A new medium, C‐EC‐agar (Biolife, Milan, Italy), was evaluated for the simultaneous enumeration by membrane filtration of faecal coliforms and Escherichia coli in water. The medium is a modification of m‐faecal coliform agar, from which the aniline blue and lactose have been omitted and 4‐methylumbelliferyl‐β‐D‐glucuronide, 5‐bromo‐4‐chloro‐3‐indolyl‐β‐ d ‐galactopyranoside and isopropyl‐β‐ d ‐thiogalactoside added. At 44°C E. coli gives blue‐green colonies that fluoresce under u.v.‐light (366 nm) and give a reddish‐violet colour when Kovac's reagent is placed on the membrane. Under similar conditions, faecal coliform colonies do not fluoresce. To increase recovery on the medium, repair of sub‐lethally injured cells by a 4‐h incubation at 37°C on tryptic soy agar is recommended.