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United States Department of Agriculture

Agricultural Research Service

Research Project: OPTICAL PROPERTIES OF SMALL GRAINS FOR RAPID AND OBJECTIVE ASSESSMENT OF QUALITY AND SAFETY Title: Improvements in Optical Sorting of Mold-Damaged Wheat

Author
item Delwiche, Stephen

Submitted to: Proceedings of SPIE
Publication Type: Proceedings
Publication Acceptance Date: November 3, 2006
Publication Date: December 1, 2006
Citation: Delwiche, S.R. 2006. Improvements in optical sorting of mold-damaged wheat. Proceedings of SPIE. 6381:63810A.

Interpretive Summary: In the United States, the authority to regulate mycotoxins, inclusive of deoxynivalenol (DON), a by-product of the fungal disease Fusarium Head Blight (FHB), is codified in the Federal Food, Drug and Cosmetic Act, which places authority with the Food and Drug Administration (FDA). Certain mycotoxins, such as aflatoxin, a recognized carcinogen, are regulated through action levels, which can then necessitate official testing for the mycotoxin and can result in the condemnation of grain lots in excess of the action level. Other mycotoxins, including DON, are not regulated by FDA, per se, but instead are voluntarily controlled under the guidelines of advisory levels. Depending on the intended use, the advisory level for DON in the United States ranges from 1 mg/kg (finished product for human consumption) to as much as 10 mg/kg (beef and chicken feed, with restrictions). This study describes the use of three forms of optical measurement of single wheat kernels for FHB for eventual incorporation in high-speed optical sorters. Our previous research has demonstrated a sorting efficiency of approximately 50 percent with existing high-speed equipment, but a much higher efficiency (~95%) when analytical spectrometers are used. The intention of the current work is to bridge this efficiency gap. Knowledge gained from analysis of the latter two forms will provide design criteria for improvement of high-speed optical sorters for recognition of mold-damaged wheat.

Technical Abstract: The current study describes the use of three forms of optical measurement of single wheat kernels for screening of Fusarium head blight for eventual incorporation in high-speed optical sorters. Our previous research has demonstrated a sorting efficiency of approximately 50 percent with existing high-speed equipment, but a much higher efficiency (~95%) when analytical spectrometers are used. The intention of the current work is to bridge this efficiency gap. Knowledge gained from analysis of the single kernel in-flight response will provide design criteria for improvement of high-speed optical sorters for recognition of mold-damaged wheat. With as few as two wavelengths, (e.g., 500 nm and 550 nm), stationary spectrometer-based classification systems are approximately 95% accurate in identifying normal and Fusarium-damaged kernels. Secondly, time-domain waveforms of the reflected energy from freefalling kernels, as sensed by a fiber optic probe, show differences between normal and Fusarium-damaged kernels on average; however, such waveforms are influenced by the random orientation of the kernel. Lastly, improvements in classification of freefalling kernels should arise with the combination of simultaneous capture of reflected light at two wavelengths and the collection of multiple reflectance readings per wavelength as the kernel traverses the detector field of view.

Last Modified: 7/22/2014
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