Effects of High Concentration-Short Time and Low Concentration-Long Time Ozone Treatments on Growth and Aflatoxin B1 Production of Aspergillus flavus in Red Pepper

Abstract

The effects of high concentration-short time (HCST) and low concentration-long time (LCLT) gaseous ozone treatments on growth and aflatoxin B1 production of Aspergillus flavus in semi-dried red pepper are presented for the first time in this paper. Potato dextrose agar (PDA) media and peppers were inoculated with a toxigenic strain of A. flavus and exposed to either HCST (1500 mu L L-1 for 1-8 h) or LCLT (0.1 mu L L-1 for 8 d) ozone treatments. Both treatments significantly inhibited A. flavus growth in PDA and peppers (p < 0.05). In pepper samples, fungal count reductions obtained by HCST and LCLT ozone treatments were around 1.57 and 1.66 log, respectively. However, the inhibitory effect decreased in time which shows that the fungus rapidly develops a resistance to ozone. The amounts of aflatoxin B-1 produced in PDA and pepper were also significantly reduced (by more than 85%) by the treatments (p < 0.05). These results demonstrate the potential of ozone treatments in preventing fungal contamination and aflatoxin production in red pepper.