The occurrence, production and stability of zearalenone and other fusarium toxins

The mycological qualities of Korean field crops were assessed by determination of internal mold infection. Fusarium semitectum and Alternaria species were the predominant fungi isolated from rice and barley. Field fungi including Curvularia and Dactylaria species were also observed. Very few fungi were isolated from wheat and bean samples. Neither zearalenone (ZEN) nor deoxynivalenol (DON) was found in cereal samples by enzyme-linked immunosorbent assay (ELISA) or high-performance liquid chromatography (HPLC). In another study, effects of temperature cycling on the growth of Fusarium graminearum, F. moniliforme and F. proliferatum, and their mycotoxin production were investigated. Incubation under cycling temperatures between 15 and 30$\sp\circ$C (CT) caused production of high levels of DON when F. graminearum was grown on rice. Production of ZEN was stimulated by incubating at a constant 15$\sp\circ$C following a 2 week incubation at 25$\sp\circ$C (LT). With LT 603 and 1679 $\mu$g/g of DON and ZEN were detected, respectively, while with CT 850 and 98 $\mu$g/g of DON and ZEN were found respectively. Different levels of growth were observed under different temperature treatments and these were correlated with the amount of DON produced. Temperature was also an important factor in the production of fumonisin B1 (FB$\sb1)$ by F. moniliforme and F. proliferatum. These two molds produced high levels of FB$\sb1$ under different cycling temperature conditions. The production of FB$\sb1$ by F. proliferatum was favored at lower temperatures when compared to that by F. moniliforme. Extrusion cooking reduced ZEN in spiked corn grits by 65-83%. The use of mixing screws was more effective than non-mixing screws in reducing ZEN as determined by HPLC. An in vitro bioassay method using a human breast cancer cell line (MCF-7) was developed to monitor the estrogenic activity of zearalenone. Relative estrogenic activity of zearalenone was determined to be 4% of that of 17$\beta$-estradiol in this assay. This cell culture assay was determined to be effective in assessing the estrogenic activity of ZEN in food samples