Influence of water activity, temperature and incubation time on the simultaneous production of deoxynivalenol and zearalenone in corn (Zea mays) by Fusarium graminearum

The production of deoxynivalenol and zearalenone by Fusarium graminearum was studied under different culture conditions (water activity, temperature and incubation time). The maximum levels of both toxins were obtained at the 35th day of incubation, the zearalenone level being much higher than the deoxynivalenol. The culture conditions that gave higher yields of deoxynivalenol were at 22 and at 28 °C (6.0 and 5.5 mg/kg ), after 35 days. At an incubation temperature of 28 °C 16 days, followed by 12 °C, for the same time, the production was low (1.1 mg/kg). The highest level of zearalenone was obtained at 28 °C for 16 days, followed by incubation at 12 °C (36.7mg/kg) at the 35th day. When the temperature was constant at 28 °C, the zearalenone production was lower (3.0 mg/kg) than when incubated at 22 °C (12.3 mg/kg), at the 35th day. Fusarium graminearum did not produce deoxynivalenol and zearalenone at 37 °C.