Submitted to: Proceedings of SPIE
Publication Type: Proceedings
Publication Acceptance Date: 12/18/2005
Publication Date: 12/30/2005
Citation: Dicrispino, K., Yao, H., Hruska, Z., Brabham, K., Lewis, D., Beach, J., Brown, R.L., Cleveland, T.E. 2005. Hyperspectral imagery for observing spectral signature change in Aspergillus flavus. Proceedings of SPIE. 5996:599606-1-10. Interpretive Summary: Aflatoxins are poisons produced by the fungus Aspergillus flavus after it infects agricultural commodities, such as corn. Since aflatoxins in food and feed are regulated, enhanced ability to detect and measure fungal growth and aflatoxin contamination of corn could contribute significantly towards the separation of contamination from healthy grain. A collaboration between ARS/SRRC, Food and Feed Safety Research Unit and the Institute for Technology Development (ITD), Stennis Space Center, MS, is exploring the use of hyperspectral imaging non-destructive technology (developed by ITD) to detect mycotoxin-producing fungi in grain products. Experiments were performed on A. flavus cultures growing over an 8-day time period to see if the spectral image of the fungus changed during growth. Results indicate that hyperspectral imaging technology can identify spectral differences associated with growth changes over time. Further experiments may lead to this technology being used to rapidly and accurately detect/measure Aspergillus flavus infection/aflatoxin contamination of corn without destruction of healthy grain. This could provide a useful tool to both growers and buyers in the corn industry that could enhance protection of food and feed, as well as increase profits.
Technical Abstract: Aflatoxin contaminated corn is dangerous for domestic animals when used as feed and cause liver cancer when consumed by human beings. Therefore, the ability to detect A. flavus and its toxic metabolite, aflatoxin, is important. The objective of this study is to measure A. flavus growth using hyperspectral technology and develop spectral signatures for A. flavus. Based on the research group’s previous experiments using hyperspectral imaging techniques, it has been confirmed that the spectral signature of A. flavus is unique and readily identifiable against any background or surrounding surface and among other fungal strains. This study focused on observing changes in the A. flavus spectral signature over an eight-day growth period. The study used a visible-near-infrared hyperspectral image system for data acquisition. This image system uses focal plane pushbroom scanning for high spatial and high spectral resolution imaging. Procedures previously developed by the research group were used for image calibration and image processing. The results showed that while A. flavus gradually progressed along the experiment timeline, the day-to-day surface reflectance of A. flavus displayed significant difference in discreet regions of the wavelength spectrum. External disturbance due to environmental changes also altered the growth and subsequently changed the reflectance patterns of A. flavus.