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Proceedings Paper

Optical methods for detecting Escherichia coli O157:H7 spiked on cantaloupes
Author(s): Shu-I Tu; Joseph Uknalis; Andrew Gehring
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Paper Abstract

Outbreaks of E. coli O157:H7 by the consumption of contaminated cantaloupes fruits have been documented. Pathogens harbored in the networked but porous veins in khaki colored skin are difficult to remove. Thus, sensitive and efficient methods are needed to detect the presence of E. coli O157:H7 in cantaloupes. In this work, known quantities of the E. coli were inoculated on cantaloupe skins or flesh at room temperature for 1 h. The contaminated samples were incubated in growth media at 37°C for 3.3h. The bacteria captured by magnetic beads coated with anti E. coli O157 antibodies were further sandwiched by second anti E. coli O157 antibodies containing peroxidase for chemiluminescent measurements of captured bacteria. Alternatively, the captured bacteria were treated with electron-shuttering reagent to detect the cellular level of NAD(P)H via bioluminescence. The detected enzyme activity (peroxidase) and the NAD(P)H were used to measure the presence of the pathogen. The results indicated both the chemiluminescence and the fluorescence methods, in 96 well microplate format, could be applied to detect the E. coli contamination of cantaloupes.

Paper Details

Date Published: 19 November 2004
PDF: 7 pages
Proc. SPIE 5587, Nondestructive Sensing for Food Safety, Quality, and Natural Resources, (19 November 2004); doi: 10.1117/12.569269
Show Author Affiliations
Shu-I Tu, U.S. Dept. of Agriculture (United States)
Joseph Uknalis, U.S. Dept. of Agriculture (United States)
Andrew Gehring, U.S. Dept. of Agriculture (United States)


Published in SPIE Proceedings Vol. 5587:
Nondestructive Sensing for Food Safety, Quality, and Natural Resources
Yud-Ren Chen; Shu-I Tu, Editor(s)

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