Animal feces are a suspected source of contamination of apples by disease-causing organisms such as <i>Escherichia coli</i> O157. Laser-induced fluorescence was used to detect different amounts of feces from dairy cows, deer, and a dairy pasture applied to Red Delicious apples. One day after application, detection for 1:2 and 1:20 dilutions was nearly 100%, and for 1:200 dilutions (<15 ng of dry matter) detection was >80%. Detection after apples had been washed and brushed was lowest for pasture feces; detection for 1:2, 1:20, and 1:200 dilutions of feces was 100%, 30%, and 0%, respectively. This technology may encourage development of commercial systems for detecting fecal contamination of apples.
© 2003 Optical Society of America
(150.3040) Machine vision : Industrial inspection
(170.0110) Medical optics and biotechnology : Imaging systems
(170.6280) Medical optics and biotechnology : Spectroscopy, fluorescence and luminescence
(300.2530) Spectroscopy : Fluorescence, laser-induced
Alan M. Lefcourt, Moon S. Kim, and Yud-Ren Chen, "Automated Detection of Fecal Contamination of Apples by Multispectral Laser-Induced Fluorescence Imaging," Appl. Opt. 42, 3935-3943 (2003)