Patent ID: 7547508

Claim:
A method for detecting fecal contamination on a surface of a fruit or vegetable which contains a native chlorophyll comprising: (a) illuminating the surface of a fruit or vegetable with a pulse of UV or visible light having a wavelength effective to elicit fluorescence of feces of an animal that directly or indirectly consumed plant products, (b) measuring the intensity of fluorescent light emissions from said surface at one or more wavelengths characteristic of the emission spectra of chlorophyll or chlorophyll degradation products, wherein said fluorescent light emissions are measured at a time period after the peak emission of the native chlorophyll of said fruit or vegetable, and (c) determining if said intensity of said fluorescent light emissions measured in (b) is significantly greater than a threshold value of the intensity of fluorescent light emissions for a non-feces contaminated control of the same fruit or vegetable measured at substantially the same conditions at substantially the same said time period and at substantially the same said wavelengths, wherein the determination that said intensity of said fluorescent light emissions measured in (b) is significantly greater than said threshold value is an indication of the presence of fecal material on said surface of said fruit or vegetable.