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Agar Medium for Enumeration of Fecal Coliforms
Author(s) -
CHEN HSINGCHEN,
WU SHEUDER
Publication year - 1992
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1992.tb06882.x
Subject(s) - enumeration , fecal coliform , feces , bromocresol purple , agar , brilliant green , food science , microbiology and biotechnology , biology , most probable number , chemistry , veterinary medicine , chromatography , bacteria , mathematics , medicine , ecology , water quality , genetics , organic chemistry , combinatorics
ABSTRACT Spread‐inoculated plates of fecal‐coliform agar (FCA) were pre‐incubated 2 hr at 35°C, and then transferred to 44.5°C for 22 hr. Fecal coliforms on FCA produce acids and CO 2 , which react with bromocresol purple and calcium lactate to form yellow to yellow‐green colonies surrounded by a pale yellow zone. Recovery of control or freeze‐stressed Escherichia coli on FCA was about 1 log cycle lower than that with nonselective media. The accuracy for FCA to enumerate fecal coliforms from 138 typical colonies of three food samples was 98.6%; while the false positive was 1.4%. When the method was compared with the standard 3‐tube MPN method for fecal coliforms, counts from two methods were not significantly different (p<0.05).