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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 #303445
Title: Multispectral fluorescence imaging for detection of bovine feces on Romaine lettuce and baby spinach leaves

Author
item LEE, HOYOUNG - Seoul National University
item EVERARD, COLM - University College - Ireland
item KANG, SUKWON - National Academy Of Agricultural Science
item CHO, BYOUNG-KWAN - Chungnam National University
item Chao, Kuanglin - Kevin Chao
item Chan, Diane
item Kim, Moon

Submitted to: Biosystems Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2014
Publication Date: 11/1/2014
Citation: Lee, H., Everard, C., Kang, S., Cho, B., Chao, K., Chan, D.E., Kim, M.S. 2014. Multispectral fluorescence imaging for detection of bovine feces on Romaine lettuce and baby spinach leaves. Biosystems Engineering. 127:125-134.

Interpretive Summary: Consumption of fresh leafy green vegetables (e.g., lettuce, and spinach) or fresh fruits that are contaminated by fecal matter can cause infection by human pathogens such as E. Coli or Salmonella. Hyperspectral fluorescence imaging technique was used to develop rapid methods for the detection of bovine fecal contaminants on the surfaces of Romaine lettuce and baby spinach leaves. In this study, two-band ratio imaging methods were developed that effectively differentiated fecal contamination spots applied to the lettuce and spinach leaves with 100 % success rates. The methods can be implemented for online inspection of produce for fecal contamination and will benefit the produce processing industries.

Technical Abstract: Hyperspectral fluorescence imaging with ultraviolet-A excitation was used to evaluate the feasibility of two-waveband fluorescence algorithms for the detection of bovine fecal contaminants on the abaxial and adaxial surfaces of Romaine lettuce and baby spinach leaves. Correlation analysis was used to select the most significant waveband pairs for two-band ratio and difference methods in distinguishing contaminated and uncontaminated leaf areas. For this investigation, two-band ratios using bands at 665.6 nm and 680.0 nm (F665.6/F680.0) for lettuce and at 660.8 nm and 680.0 nm (F660.8/F680.0) for spinach effectively differentiated all contamination spots applied to the lettuce and spinach leaves, respectively. The fluorescence emission peaks for the fecal matter of animals that consume green plant materials and for chlorophyll A occur in close proximity in the red spectral region. Consequently, a high spectral resolution would be required for multispectral imaging with these two-band ratios for online implementation to detect bovine fecal contamination on leafy greens such as Romaine lettuce and baby spinach.