Control Mycotoxin Contamination In Corn With Ozone Gas

In this thesis, we applied O3to control the contamination of fungi and their metabolism on corn during the storage. The effect of ozone treatment on the growth of Aspergillus ochraceus and Penicillium viridicatum and the degradation of ochratoxin A (OTA), the effects of O3on corn germination and quality of storaged corn were studied. The main results are as follows:Aspergillus ochraceus and Penicillium viridicatum were treated by different ozone concentration10g/m3,30g/m3,60g/m3) respectively. The results demonstrated that all of the different concentrations of ozone have an effect on the growth and colony morphology of Aspergillus ochraceus and Penicillium viridicatum.6.18logcfu/mL of Aspergillus ochraceus and6.471ogcfu/mL of Penicillium viridicatum were completely destroyed when exposed to O3at10g/m3,30g/m3,60g/m3respectively for20,15and10min. The growth of Aspergillus ochraceus and Penicillium viridicatum at25℃for7days were completely inhibitioned when exposed to30g/m O3for60, and90min respectively. O3can destroyed the colony morphology of Aspergillus ochraceus and Penicillium viridicatum.The effects of ozone concentration(10g/m3,30g/m3,60g/m3) and exposure time (1～10h) on the degradation of OTA were also evaluated. Results showed that, when80μg/L of OTA treated by30g/m3O3for120min or60g/m3O3for90min, the degradation rate is97.6%and98.7%respectively. While treated by10g/m3O3for120min, the degradation rate is45.7%.80μg/kg of OTA spiked on corn was degraded to under5μg/kg after being treated by60g/m3O3for10h.There is no effect of lower concentration of O3(10g/m3) on the germination of corn, but the germination rate of corn were decreased to85%,85%and75%after being exposed to30g/m3O3for5hours and60g/m3O3for1and5hours. O3had little effect on the fatty acids of corn.Based on the above results, O3was applied in the storage of corn. The evaluation showed that the quality of corn with ozone treatment is better than the untreated corn when storaged for two months. The treatment with O3have an effective reduction of fungi and ochratoxin A on the contaminated corn. Ozone treatment can improve the quality and safety of storaged corn.