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Response of Aspergillus flavus spores to nitric oxide fumigations in atmospheres with different oxygen concentrations

Liu, Yong-Biao, Oh, Sookyung, Jurick, Wayne M.
Journal of stored products research 2019 v.83 pp. 78-83
Aspergillus flavus, cellulose, fumigants, fumigation, microorganisms, nitric oxide, nitrogen dioxide, oxygen, pest control, pests, spores, stored products
Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. NO fumigation must be conducted under ultralow oxygen conditions because NO reacts with O2 to produce nitrogen dioxide (NO2). In this study, NO fumigations under different O2 concentrations were conducted on Aspergillus flavus spores to determine effectiveness of NO and NO2 in inactivating spores. Spores on gridded cellulose filter discs in Petri dishes were subjected to six fumigation treatments including a control with varying levels of NO under different O2 conditions for 3 h at 15 °C. The discs with spores were then cultured on Aspergillus Differentiation medium plates after fumigation for four days at 25 °C to count A. flavus colonies. Untreated control discs each had over 50 A. flavus colonies. Three fumigation treatments with 0.1% NO2 or 1.0% NO caused complete inactivation of A. flavus spores. The study demonstrated that NO fumigation with certain levels of NO2 can effectively inactivate A. flavus spores. The results suggest that NO fumigation has potential to be an alternative treatment to control both pests and microbes on stored products.