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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #328175
Title: Identifying fecal matter contamination in produce fields using multispectral reflectance imaging under ambient solar illumination

Author
item EVERARD, COLM - University College Dublin
item Kim, Moon
item LEE, HOONSOO - Forest Service (FS)
item O'DONNEL, COLM - University College Dublin

Submitted to: Proceedings of SPIE
Publication Type: Proceedings
Publication Acceptance Date: 4/13/2016
Publication Date: 5/17/2016
Citation: Everard, C., Kim, M.S., Lee, H., O'Donnel, C.P. 2016. Identifying fecal matter contamination in produce fields using multispectral reflectance imaging under ambient solar illumination. Proceedings of the SPIE 9864, Sensing for Agriculture and Food Quality and Safety VIII, 986416.

Interpretive Summary: A two-waveband imaging device was developed for detecting fecal contamination in fresh produce fields, which could help producers to avoid harvesting fecal-contaminated leafy green vegetables. The use of this device could help prevent cases of foodborne illness, such as past E.coli O157:H7 outbreaks that have been associated with fecal-contaminated leafy green vegetables. Spots of soil and fecal matter were applied to spinach leaves. The device acquired spectral images of the spinach leaves at two wavebands, 690 nm and 710 nm. Analysis of ratio images from these two wavebands showed that the fecal matter contamination could be distinguished from areas of soil and leaves in the ratio images. Not only is this technology a potential tool for detecting fecal contamination in produce fields before harvesting occurs, it may also help mitigate cross-contamination during harvesting and processing operations for ready-to-eat greens headed to market, ultimately benefiting producers, processors, and consumers of fresh produce.

Technical Abstract: An imaging device to detect fecal contamination in fresh produce fields could allow the producer to avoid harvesting fecal-contaminated produce. E.coli O157:H7 outbreaks have been associated with fecal-contaminated leafy greens. In this study, in-field spectral profiles of bovine fecal matter, soil, and spinach leaves are compared. A common aperture imager designed with two identical monochromatic cameras, a beam splitter, and two optical filters was used to simultaneously capture two-waveband spectral images of leaves contaminated with both fecal matter and soil. The two optical bandpass filters were centered at 690 nm and 710 nm, each 10nm full width at half maximum. These were mounted in front of the object lenses. New images were created using the ratio of the two spectral images on a pixel-by-pixel basis. Image analysis results showed that the fecal matter contamination could be distinguished from soil and leaf areas on the ratio images. The use of this technology has potential to allow detection of fecal contamination, which can be a source of foodborne illnesses, in fresh produce production fields, and has the added benefit of mitigating cross-contamination during harvesting and processing.