Mechanically Cleaning Corn Reduces Fumonisin Concentration

Fumonisin is one of the most prevalent and harmful mycotoxins that can be present in corn. When fed higher concentrations for extended periods of time, fumonisin can lower growth performance and cause disease. Fumonisin is often concentrated in broken kernels because there is exposed substrate for mold growth. While some research has evaluated the role of mechanical cleaning to reduce fumonisin levels in corn, it has largely been evaluated in grain that was artificially contaminated to limit variability. Therefore, the objective of this experiment was to quantify the magnitude of natural fumonisin concentration that may be reduced by removing broken corn and foreign material by mechanically cleaning it using a corn cleaner. A single load of corn that was naturally contaminated with fumonisin, was procured from south central Kansas. The corn was moved to and cleaned at Kansas State University. Corn was divided into twenty 150 kg lots, which were then cleaned using a commercial corn cleaner (Gentle Roll, EBM Manufacturing, Norfolk, NE) to remove overs (material > 12.7-mm) and thrus (material < 4.76-mm) to establish 3 treatments: 1) uncleaned corn; 2) cleaned corn; and 3) screenings (overs + thrus). The corn cleaner was sanitized between each of the 20 lots. Three 5-kg samples of corn were collected by probing from each treatment of each lot, ground via hammermill, riffle divided, and analyzed for mycotoxin concentration using multiclass liquid chromatography tandem mass spectrometry. Data were analyzed using the GLIMMIX procedure of SAS, with lot as the experimental unit. The uncleaned corn had 5.5 ppm fumonisin, but no other mycotoxin detected. Cleaning generated 2.2% screenings by weight, which had substantially greater (P < 0.05; 65.4 ppm) fumonisin than the uncleaned or cleaned corn. Cleaning reduced (P < 0.05; 3.3 ppm) fumonisin concentration in cleaned corn by an average of 60% compared to the uncleaned corn. While the uncleaned corn had only moderate levels of fumonisin concentration, this research demonstrates the ability of mechanical cleaning to further reduce concentration. Furthermore, it highlights the substantial potential concentration of fumonisin that may be present in corn screenings, even in years of mild mycotoxin pressure.