Submitted to: Cereal Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/4/2004
Publication Date: 6/1/2004
Citation: Pearson, T.C., Wicklow, D.T., Pasikatan, M.C. 2004. Reduction of aflatoxin and fumonisin contamination in yellow corn by high-speed bi-chromatic sorting. Cereal Chemistry. 2004. 81(4):490-498. Interpretive Summary: A method for optimizing a bi-chromatic sorter was developed and applied to sorting mycotoxin contaminated corn. It was found that using spectral absorbances at 750 hm and 1200 hm could distinguish kernels with aflatoxin-contamination greater than 100ppb from kernels with no detectable aflatoxin with over 98% accuracy. When these two spectral bands were applied to sorting corn at high speeds, reductions in aflatoxin averaged 82% for corn samples with an initial level of aflatoxin over 10 ppb. Most of the aflatoxin is removed by rejecting approximately 5% of the grain. Fumonisin is also removed along with aflatoxin during sorting. The sorter reduced fumonisin by an average of 88% for all samples.
Technical Abstract: A high speed bi-chromatic sorter was tested for removing corn contaminated in the field with aflatoxin and fumonisin. To achieve accurate sorting, single kernel reflectance spectra (500-1700 hm) was analyzed to select the optimal pair of optical filters to detect mycotoxin contaminated corn during high speed sorting. A routine, based on discriminant analysis, was developed to select the two absorbance bands in the spectra that would give the greatest classification accuracy. It was found that in a laboratory setting and with the kernels stationary, absorbances at 750 and 1200 hm could correctly identify over 99% of the kernels as aflatoxin-contaminated (over 100ppb) or uncontaminated. A high-speed sorter was tested using the selected filter pair using corn samples of A. flavus-inoculated and naturally infested corn grown in central Illinois and naturally infested, commercially grown and harvested corn from eastern Kansas (2002 harvest). For the Kansas corn, the sorter was able to reduce aflatoxin levels by 81% from an initial average of 53 ppb, while fumonisin levels in the same grain samples were reduced an average of 85% from an initial level of 17 ppm. Similar reductions in mycotoxin levels were observed following high-speed sorting of A. flavus-inoculated and naturally mold-infested corn grown in Illinois.