Concentrations and toxicity of fumonisin B1 in fermented corn grits are reduced by extrusion cooking with glucose supplementation

Authors: Voss, Kenneth; JACKSON, L - Us Food & Drug Administration (FDA); JABLONSKI, J - Us Food & Drug Administration (FDA); BIANCHINI, A - University Of Nebraska; HANNA, M - University Of Nebraska; BULLERMAN, L - University Of Nebraska; RYU, D - Texas Woman'S University

Submitted to: Proceedings of the US Japan Joint Panel on Toxic Microorgnisms
Publication Type: Abstract Only
Publication Acceptance Date: 11/8/2009
Publication Date: 11/8/2009
Citation: Voss, K.A., Jackson, L.S., Jablonski, J.E., Bianchini, A., Hanna, M.A., Bullerman, L.B., Ryu, D. 2009. Concentrations and toxicity of fumonisin B1 in fermented corn grits are reduced by extrusion cooking with glucose supplementation. Proceedings of the US Japan Joint Panel on Toxic Microorgnisms. November 8-13, 2009. Tokyo, Japan. p. 12.

Interpretive Summary: Abstract - no summary required.

Technical Abstract: Extrusion is a cooking method in which dough is forced under high pressure through a heated barrel using one (single-screw configuration) or two (twin-screw configuration) augers. In an earlier experiment (Voss et al., J. Food Protec. 71: 2036-2041, 2008), extrusion using the single screw configuration reduced fumonisin concentrations of three batches of contaminated corn grits. Adding glucose before cooking increased the reductions that were achieved and partially reversed the renal toxicity of one batch as determined by a 3-week rat feeding bioassay, The purpose of this study was to determine the effectiveness of the more efficient twin-screw configuration to reduce fumonisin concentrations and in vivo toxicity of the grits. Two batches of Fusarium verticillioides-fermented corn grits (Batch-1 contained 9.7 ppm fumonisin B1 (FB1); Batch-2 contained 50 ppm FB1 as determined by HPLC-fluorescence) were extruded (Batch-1E; Batch-2E) or extruded with 10% w/w glucose supplementation (Batch-1EG; Batch-2EG) using a twin-screw apparatus. FB1 concentrations of the extruded grits were also determined (HPLC) and were: Batch-1E = 2.7 ppm; Batch-1EG = 0.6 ppm; Batch-2E = 18 ppm; and Batch-2EG = 5.7 ppm. These values corresponded to FB1 reductions of 72% (Batch-1E), 94% (Batch-1EG), 64% (Batch-2E) and 89% (Batch-2EG). Batch-1, Batch-1E, Batch-1EG, Batch-2, Batch-2E, Batch-2EG as well as uncooked (control) or extruded (extrusion control) uncontaminated (<0.2 ppm FB1) corn grits were mixed (1:1) with basal rodent chow and fed to young male rats for 3 (n=5/group) or 8 (n=5/group) weeks. No significant differences in general appearance, body weights or detailed hematology and serum chemistry profiles were found. The kidney is the most sensitive target organ of fumonisins in male rats and evidence of renal toxicity was found in five of the six test groups. Specifically, relative kidney weights were decreased in groups fed the Batch-1 or Batch-2 diets while apoptotic tubule lesions consistent with fumonisin-induced nephropathy were found upon microscopic exanimation of the kidneys from animals fed the Batch-1, Batch-1E, Batch-2, Batch-2E, or Batch-2EG diets. Lesions were most severe in the groups fed diets having the highest FB1 concentrations: that is, Batch-1 (diet FB1 = 4.9 ppm), Batch-2 (25 ppm) and Batch-2E (9.0 ppm). Less severe, minimal to mild changes were evident in the Batch-1E (1.4 ppm) or Batch-2EG (2.9 ppm) groups whereas no lesions were found in the rats fed the Batch-1EG (0.3 ppm) diet, which contained the lowest levels of residual FB1. Taken together, the chemical analysis and bioassay findings indicate that extrusion with glucose using a twin-screw configuration reduces FB1 concentrations of contaminated corn grits and confirm that glucose supplementation enhances FB1 reductions as well as the in vivo toxic potential of the extrusion cooked grits.