| The most sensitive mammalian cell lines to Fusarium mycotoxins, deoxynivalenol (DON), zearalenone (ZEN), fumonisin (FUM), and moniliformin (MON), were investigated for further toxicological investigations as alternatives to whole animal testing for screening extracts of Fusarium spp. contaminated foods and feeds. The Chinese hamster ovary (CHO-K1) for DON and FUM, hepatocel lular carcinoma (HepG2) for MON, and Balb/c mice keratinocyte (C5-O) for ZEN were found to be the most sensitive cell lines with IC50 values of 0.27, 85.5, 26.8, and 24.1 mug/ml, respectively, as measured by the MTT bioassay. In the following study, reduced DON concentrations in contaminated corn grits after extrusion were analyzed by chemical (HPLC) and biochemical (ELISA) methods. The loss of toxicity of DON was confirmed by the MTT bioassay using the CHO-K1 cell line. Extrusion temperatures of 160, 180, 200 and 220°C and screw speeds of 50, 80, 110 and 140 rpm significantly reduced DON levels in contaminated corn grits by 22--35% (P < 0.05). A second extrusion processing was designed to evaluate reduction of levels of both DON and ZEN in F. graminearum contaminated corn grits. This was analyzed by HPLC and ELISA, and reduced toxicity a was confirmed by the MTT bioassay. The CHO-K1 cells was used to evaluate the cytotoxicity of DON, whereas the adenocarcinoma human breast cells (MCF-7), which has estrogen receptors, was used to evaluate the estrogenic activity of ZEN. The effect of extrusion temperatures of 150, 175, and 200°C was found to be a linear, with DON reduced by 22--35%, whereas a quadratic response on reduced ZEN by 67--81%. The MTT bioassay results were more closely correlated with the HPLC results (r = 0.90 for DON, r = 0.96 for ZEN) than the ELISA results (r = 0.78 for DON, 0.83 for ZEN). The MTT bioassay was proved to be a useful method for quantification of DON and ZEN, as well as a potential toxicity screening method for contaminated extruded cereal based products. |
