Efficacy of ozone in the microbiological disinfection of maize grains

Abstract This research aimed to determine the effectiveness of ozone in the microbiological disinfection of maize grains. Two kg samples of maize grains were used with moisture contents of 14.4% (w.b.), and 94% and 97% of natural infection by Penicillium spp and Aspergillus spp, respectively. The gas was applied at a concentration of 2.14 mg L-1 and flow rate of 5.8 L min-1 for 370 min at 25 ºC ± 2 ºC in order to determine the ozone concentration and saturation time of the maize grains. The experiment was installed according to a split plot design, with two treatments in the plots (atmospheric air and ozone gas) and exposure times of (0, 10, 20, 30 and 50 h) in the subplots, in a completely randomized design. It was shown that the ozone concentration and saturation time in the grain mass were 0.9874 mg L-1 and 138.56 min, respectively. Ozonation was effective in controlling storage fungi in the grain mass with 50 h of exposure to the gas, reducing the rate of incidence of Aspergillus spp (78.5%) and Penicillium spp (98.0%), thereby confirming its fungicidal effect under the conditions presented.

摘要 本研究旨在探究臭氧对玉米籽粒进行微生物消毒的应用效果。试验采用2 kg玉米籽粒样品，其含水率为14.4%（湿基，w.b.），自然感染青霉菌属（Penicillium spp.）与曲霉菌属（Aspergillus spp.）的比例分别为94%和97%。于25℃±2℃环境中，以2.14 mg·L⁻¹的臭氧浓度、5.8 L·min⁻¹的气流速率处理370 min，以测定玉米籽粒体系中的臭氧浓度与饱和时间。试验采用裂区设计（split plot design）：主区设置2种处理（大气空气与臭氧气体），副区设置5个暴露时长（0、10、20、30和50 h），整体采用完全随机设计（completely randomized design）。结果表明，粮堆内的臭氧饱和浓度与饱和时间分别为0.9874 mg·L⁻¹与138.56 min。经50 h臭氧暴露处理后，臭氧消毒可有效抑制粮堆中的仓储真菌，曲霉菌属侵染率降低78.5%，青霉菌属侵染率降低98.0%，从而证实了本试验条件下臭氧的杀菌效果。