Abstract
A single-step most-probable-number method for enumerating fecal coliforms in sewage treatment plant effluents is described. The method requires the use of only one lactose-based medium and a single incubation temperature of 44.5 degrees C, and it can be completed in 18 h or less, as compared with up to 72 h for the standard most-probable-number method. The appearance of growth is the sole criterion used for designating positives, which can be determined either by increases in the electrical impedance ratio of inoculated medium, as compared to an uninoculated control using a Bactometer model 32, or by visual examination of inoculated medium for turbidity. In trials with 53 samples of unchlorinated sewage treatment plant effluent, fecal coliform counts by the single-step most-probable-number method, throughout a range of less than 10 to almost 10(7) fecal coliforms per 100 ml of effluent, were in excellent agreement with counts abtained by the standard most-probable-number procedure. Similar agreement was obtained in comparative trials with 31 chlorinated effluent samples from two sewage treatment plants. Overall, 87% of 452 positives were confirmed as containing fecal coliforms. The applicability of the single-step most-probable-number method to automated sewage treatment plant operations is discussed.
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Selected References
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- Green B. L., Clausen E. M., Litsky W. Two-temperature membrane filter method for enumerating fecal coliform bacteria from chlorinated effluents. Appl Environ Microbiol. 1977 Jun;33(6):1259–1264. doi: 10.1128/aem.33.6.1259-1264.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hardy D., Kraeger S. J., Dufour S. W., Cady P. Rapid detection of microbial contamination in frozen vegetables by automated impedance measurements. Appl Environ Microbiol. 1977 Jul;34(1):14–17. doi: 10.1128/aem.34.1.14-17.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lin S. Evaluation of coliform tests for chlorinated secondary effluents. J Water Pollut Control Fed. 1973 Mar;45(1):498–506. [PubMed] [Google Scholar]
- Rose R. E., Geldreich E. E., Litsky W. Improved membrane filter method for fecal coliform analysis. Appl Microbiol. 1975 Apr;29(4):532–536. doi: 10.1128/am.29.4.532-536.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Silverman M. P., Munoz E. F. Automated electrical impedance technique for rapid enumeration of fecal coliforms in effluents from sewage treatment plants. Appl Environ Microbiol. 1979 Mar;37(3):521–526. doi: 10.1128/aem.37.3.521-526.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stuart D. G., McFeters G. A., Schillinger J. E. Membrane filter technique for the quantification of stressed fecal coliforms in the aquatic environment. Appl Environ Microbiol. 1977 Jul;34(1):42–46. doi: 10.1128/aem.34.1.42-46.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]