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Proceedings Paper

Rapid detection of Escherichia coli in aqueous samples by metabolic induced change in pH
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Paper Abstract

Escherichia coli bacteria are a source of food related illness. If irrigation water is contaminated by fecal matter runoff, crops may become infected prior to harvesting, processing, or packaging. Existing test methods require 16-48 hours for confirmation of bacterial infection in the irrigation water. Therefore, providing a means for a rapid detection of water borne coliform and E. coli within a typical workday of 8-10 hours would allow a preventative response. We have developed a method to determine bacteria presence by a measure of metabolic activity with a spectral analysis system. Metabolic activity of live bacteria will appear as a drop in solution pH in a relatively short time frame during the growth phase of the cultured bacteria. A blue LED is used to excite fluorescein fluorescence in the bacterial growth media. The fluorescence exhibits pH sensitive spectral properties within a range of pH 4-7. Unmixing of the fluorescence spectral profile yields the pH and confirms a growing bacteria culture. Results can be provided in hours instead of days, depending on the initial concentration of living bacteria.

Paper Details

Date Published: 20 February 2020
PDF: 7 pages
Proc. SPIE 11233, Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications XX, 112331E (20 February 2020); doi: 10.1117/12.2545283
Show Author Affiliations
Noah R. Baker, Univ. of Washington (United States)
Leonard Y. Nelson, Univ. of Washington (United States)
Eric J. Seibel, Univ. of Washington (United States)

Published in SPIE Proceedings Vol. 11233:
Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications XX
Israel Gannot, Editor(s)

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