Aflatoxin Reduction in Corn by Cleaning and Sorting

Abstract

<abstract> <bold>Abstract. </bold>Mycotoxins reduce quality of corn by causing health problems for livestock and humans that ingest the affected corn. They are generally thermally stable and difficult to degrade using chemical treatments without negatively affecting corn quality. The effectiveness of cleaning and kernel sorting in reducing aflatoxin levels in corn was studied. Differences between the physical properties of moldy and healthy corn kernels were determined, including size, shape and density. There were statistically significant differences between moldy and healthy corn kernels in major diameter, minor diameter, sphericity, and density. The averages for these attributes were 12.016 mm, 5.337 mm, 0.644, and 1.215 g/cm³ for healthy kernels, and 10.551 mm, 5.969 mm, 0.757, 1.147 g/cm³for moldy kernels, respectively. A test was also conducted at a commercial seed corn processing facility using a screen cleaner and a gravity table. The aflatoxin level in the fines removed with a 5.16 mm screen was 1404 ppm, which was approximately 46 times the level in the overs. In two successive passes through the screen cleaner, the aflatoxin levels in the material removed with a 6.75 mm screen were 246 and 197 ppm, respectively, which are 7 and 15 times the levels in the overs. Aflatoxin levels in lower density kernels removed by two successive passes through the gravity table were 384 and 342 ppm, respectively. These are >50 times the level in the higher density kernels. These results indicate that it is possible to significantly reduce aflatoxin levels in at least some corn lots by removing fine material along with smaller particles and lower density kernels. Kernel densities and their distributions were also determined for several of the samples.