MULTISPECTRAL LASER-INDUCED FLUORESCENCE IMAGING SYSTEM FOR LARGE BIOLOGICAL SAMPLES

Authors: Kim, Moon; Lefcourt, Alan; Chen, Yud

Submitted to: Applied Optics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2003
Publication Date: 7/1/2003
Citation: KIM, M.S., LEFCOURT, A.M., CHEN, Y.R. MULTISPECTRAL LASER-INDUCED FLUORESCENCE IMAGING SYSTEM FOR LARGE BIOLOGICAL SAMPLES. APPLIED OPTICS. 42(19):3927-3934. 2003.

Interpretive Summary: Feces from dairy cows and deer are suspected of being sources of contamination of apples by disease causing organisms. Fecal contamination of meats often occurs during the slaughtering process. Government regulations stipulate no-visual evidence of fecal matter on meats and on fruits used to make juices. To date, there are no reliable, automated, non-invasive sensing systems for detection of fecal contamination on agricultural products that can be employed in processing plants. Using laser-induced fluorescence techniques, the ISL has developed a very sensitive multispectral imaging system for detection of fecal contamination of agricultural products. The versatility of the system was demonstrated with test images of apples and pork meats artificially contaminated with dilute animal feces. Regions of fecal contamination that was not readily visible to human eye were easily identified in the multispectral fluorescence images. This technology can be used to evaluate the effectiveness of common food handling procedures such as the washing of fruit prior to juice making, and could be incorporated into commercial systems to detect fecal contamination in food processing plants; the potential beneficiaries are food producers and consumers.

Technical Abstract: Presented is a detailed description of a common aperture, multispectral laser-induced fluorescence imaging system developed to allow detection of fecal matter on agricultural products. With an expanded, 355 nm, Nd:YAG laser beam as the excitation source, fluorescence emission images in the blue, green, red, and far-red regions of the spectrum centered at 450, 550, 678, and 730 nm, respectively, are captured simultaneously from a 30 cm diameter target area. Test images of apples and pork meats, artificially contaminated with diluted animal feces, demonstrated the potential of this imaging technique. Regions of contamination could be easily identified from the images, including the sites that were not readily visible to the human eye. The fluorescence technique may be an appropriate basis for development of commercial system for detecting fecal contamination on apples and meats in the processing plants.