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Proceedings Paper

Ns-scale time-resolved laser induced fluorescence imaging for detection of fecal contamination on apples
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Paper Abstract

Our laboratory has been utilizing fluorescence techniques as a potential means for detection of quality and wholesomeness of food products. A system with a short pulse light source such as a laser coupled with a gated detector can be used to harvest fluorescence in ambient light conditions from biological samples with relatively low fluorescence yields. We present a versatile multispectral laser-induced fluorescence (LIF) imaging system capable of ns-scale time resolved fluorescence. The system is equipped with a tunable pulse laser system that emits in the visible range from 410 nm to 690 nm. Ns-scale, time-dependent multispectral fluorescence emissions of apples contaminated with a range of diluted cow feces were acquired. Four spectral bands, F670, F680, F685 and F730, centered near the emission peak wavelengths of the major constituents responsible for the red fluorescence emissions from apples artificially contaminated with cow feces were examined to determine a suitable single red fluorescence band and optimal ns-gate window for detection of fecal contamination on apples. The results based on the ns decay curves showed that 670 nm with 10 nm full width at half maximum (FWHM) at a gate-delay of 4 ns from the laser excitation peak provided the greatest differences in time-dependent fluorescence responses between feces contaminated spots and apples surfaces.

Paper Details

Date Published: 19 November 2004
PDF: 8 pages
Proc. SPIE 5587, Nondestructive Sensing for Food Safety, Quality, and Natural Resources, (19 November 2004); doi: 10.1117/12.582042
Show Author Affiliations
Moon S. Kim, U.S. Dept. of Agriculture (United States)
Alan M. Lefcourt, U.S. Dept. of Agriculture (United States)
Yud-Ren Chen, 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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