Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: August 31, 2004
Publication Date: N/A
Fluorescence is widely used for investigation of biological materials, and in recent years it has also been used to monitor food quality and safety. In this study the hyperspectral imaging system developed at the Instrumentation and Sensing Laboratory (ISL), United States Department of Agriculture (USDA) was used to evaluate the potential for detection of animal fecal contamination on cantaloupes and strawberries. Samples obtained from a local store were rinsed and allowed to air dry. Subsequently, fresh cow feces collected from the USDA dairy were diluted 1:10, 1:50, and 1:100 by weight with H2O and applied to the samples. Samples were excited using a UVA source and fluorescence responses were measured from 430 to 770 nm. Results indicate that fluorescence images at 680nm exhibited the greatest contrast between treated and untreated surfaces. For cantaloupes, contrast was improved using ratio images where images at 660 nm were divided by images at 560 nm. For strawberries, contrast was improved using the ratio of images at 680 nm and 745 nm. When data were analyzed for principle components (PC), the first four PC images exhibited useful results for contamination detection. Leaves present a problem when trying to identify fecal contamination on strawberries, however PC-3 provided contrast between them, creating ideal conditions for leaf masking. For cantaloupes, the PC-2 image differentiated contaminated regions. PC-1 presented distinctive differences between the contaminated spots and cantaloupe scarred tissue, suggesting possible use for such discrimination.