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Rapid, single-step most-probable-number method for enumerating fecal coliforms in effluents from sewage treatment plantsA single-step most-probable-number method for determining the number of fecal coliform bacteria present in sewage treatment plant effluents is discussed. A single growth medium based on that of Reasoner et al. (1976) and consisting of 5.0 gr. proteose peptone, 3.0 gr. yeast extract, 10.0 gr. lactose, 7.5 gr. NaCl, 0.2 gr. sodium lauryl sulfate, and 0.1 gr. sodium desoxycholate per liter is used. The pH is adjusted to 6.5, and samples are incubated at 44.5 deg C. Bacterial growth is detected either by measuring the increase with time in the electrical impedance ratio between the innoculated sample vial and an uninnoculated reference vial or by visual examination for turbidity. Results obtained by the single-step method for chlorinated and unchlorinated effluent samples are in excellent agreement with those obtained by the standard method. It is suggested that in automated treatment plants impedance ratio data could be automatically matched by computer programs with the appropriate dilution factors and most probable number tables already in the computer memory, with the corresponding result displayed as fecal coliforms per 100 ml of effluent.
Document ID
Document Type
Reprint (Version printed in journal)
Munoz, E. F. (NASA Ames Research Center Moffett Field, CA, United States)
Silverman, M. P. (NASA Ames Research Center Extraterrestrial Research Div., Moffett Field, Calif., United States)
Date Acquired
August 9, 2013
Publication Date
March 1, 1979
Publication Information
Publication: Applied and Environmental Microbiology
Volume: 37
Subject Category
Distribution Limits