MULTISPECTRAL LASER INDUCED FLUORESCENCE IMAGING TECHNIQUES FOR NONDESTRUCTIVE ASSESSMENT OF POSTHARVEST FOOD QUALITY AND SAFETY

Ns-scale, time dependent fluorescence emission characteristics of apples contaminated with a range of diluted cow feces were acquired using a recently developed multispectral laser-induced fluorescence imaging system.
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 and animal feces were examined.
The objective of the study was to investigate ns-scale fluorescence emission characteristics of samples to determine a suitable single red fluorescence band and optimal gate-delay time for detection of fecal contamination on apples.
The results based on the ns decay curves show that 670 nm with 10 nm FWHM provides the greatest difference in time-dependent fluorescence responses of feces treated and untreated apples surfaces at a gate-delay of 4 ns from the laser excitation peak.
With these detection parameters, fluorescence emissions from the diluted feces spot account for a minimum of 27% of the total emissions.

V International Postharvest Symposium

M.S. Kim, A.M. Lefcourt, Y.-R. Chen

fluorescence imaging, fluorescence decay, gate-delay, laser-induced fluorescence, animal fecal contamination, apples

https://doi.org/10.17660/ActaHortic.2005.682.185