Potential of gaseous ozone to inhibit Aspergillus flavus and detoxify aflatoxin B1 in agar and broth media (solid and liquid food states) at different growth phases

Abstract

Agricultural food crops are prone to Aspergillus flavus contamination during post-harvest and storage stages. Their consumption is toxic due to aflatoxin production, a potent carcinogenic and immunosuppressive agent. Present study explored the ozone's effect as a function of food media states (solid and liquid) to inhibit Aspergillus flavus under three modes of treatment (0th-day, Every-day and Nth-day ozone treatment), that adds novelty to the work. Results showed that ozone concentration to treat Aspergillus flavus and aflatoxins is higher in liquid than solid food state. Further, ozone treatment affected the intactness of fungal spores and inhibited 100% conidial growth. It also exhibited 88 %% inhibition and 90% reduced biomass in solid and liquid food states. Effectiveness of ozone towards inhibiting Aspergillus flavus and aflatoxin was in the following order: Nth -day treatment > Every-day treatment > 0th -day ozone treatment. Further, growth studies showed ozone treated cultures exhibit delayed sporulation and aflatoxin production by 72 h. when cultured on fresh media. Additionally, ozone purging into extracted aflatoxin led to > 99% degradation. The above results show the significance of ozone technology in increasing the shelf-life of post-harvested food crops. Further, it can be used as a disinfectant in the food industry to treat contaminated food crops/liquid products by detoxifying aflatoxins.