Evaluation of reduced toxicity of zearalenone by extrusion processing as measured by the MTT cell proliferation assay.

The objective of this study was to determine loss of toxicity of zearalenone in extruded cereal-based products by the MTT (tetrazolium salt) cell proliferation assay using a sensitive MCF-7 human breast cancer cell line and to compare the results to chemical (high-performance liquid chromatography, HPLC) and biochemical (enzyme-linked immunosorbent assay, ELISA) methods of analysis. A split-split plot design was used for the extrusion process experiments at temperatures of 150, 175, and 200 degrees C and screw speeds of 70 and 140 rpm. The initial zearalenone concentration in the artificially contaminated corn grits with Fusarium graminearum was found at a mean concentration of 37.88 microg/g as measured by HPLC. The percent reductions of zearalenone in the contaminated corn grits upon extrusion processing were in the ranges of 67-81, 60-72, and 66-78% as measured by HPLC, ELISA, and the MTT cell proliferation assay, respectively. The MTT cell proliferation assay results were more closely correlated with HPLC results (r = 0.96) than ELISA results (r = 0.83). The MTT cell proliferation assay was demonstrated to be a useful method for quantification of zearalenone as well as a potential toxicity screening method for contaminated extruded cereal-based products.