臭氧水消毒效果的试验研究

本文介绍了利用臭氧水对大肠肝菌、枯草杆菌芽胞、绿霉菌和金黄色葡萄球菌的杀菌机理以及在不同条件下的灭菌效果。探讨了氧水的特性及对血清中ＨＢｓＡｇ的破坏作用     

肉桂油制苯甲醛的反应过程研究

通过肉桂油在臭氧氧化作用下生成苯甲醛的反应，研究了肉桂油的反应过程和反应传质总理２，并探讨了反应物浓度随反应的变化关系，为肉桂油的深度加工进行中试和工业化生产提供了理论依据。     

香蕉工厂化繁殖中微生物污染的控制

以香蕉吸芽为材料，研究不同季节取材、消毒方法、继代培养容器外表面的臭氧灭茵处理和简易大棚炼苗环境的甲醛熏蒸对控制香蕉工厂化繁殖中微生物污染的效果。结果表明，采用0．2％HgCl2浸泡10min后，换0．2％ HgCl2再浸泡10min的消毒方法获得无茵外植体的成功率较高，且外植体低代增殖率较高；秋冬季采芽获得无茵外植体的成功率显著高于春夏季；臭氧处理继代培养容器外表面既可以显著降低继代丛芽的污染率，又能够显著地提高工作效率和节约劳动成本；甲醛熏蒸简易大棚内环境可以显著降低香蕉试管苗炼苗期间的微生物污染，提高出苗率。     

Effect of ultraviolet-C light on quality and microbial population of fresh-cut watermelon

The influence of ultraviolet (UV-C) light (1.4–13.7 kJ m⁻² at 254 nm) on the quality and microbial populations of fresh-cut watermelon [Citrulus lanatus (Thunb.) Matsum. and Nakai] was investigated and compared to that of common sanitizing solutions used for fresh-cut produce. Dipping cubes in chlorine (40 μL L⁻¹) and ozone (0.4 μL L⁻¹) was not effective in reducing microbial populations and quality was lower in cubes receiving these aqueous treatments compared to UV-irradiated cubes or control. In commercial trials, exposing packaged watermelons cubes to UV-C light at 4.1 kJ m⁻² produced >1 log reduction in microbial populations by the end of the product's shelf life without affecting juice leakage, color and, overall visual quality. In further experimentation, lower UV-C dose (1.4 kJ m⁻²) reduced microbial populations to a lower degree and only when complete surface exposure was ensured. Higher UV-C doses did not show any difference in microbial populations (6.3 kJ m⁻²) or result in quality deterioration (13.7 kJ m⁻²). Spray applications of hydrogen peroxide (2%) and chlorine (40 μL L⁻¹), without subsequent removal of excess water, failed to further decrease microbial load of cubes exposed to UV-C light at 4.1 kJ m⁻². When properly utilized, UV-C light is the only method tested in this study that could potentially be used for sanitizing fresh-cut watermelon.     

不同浓度臭氧对循环水养殖系统生物膜活性及其净化效能的影响

本文通过在循环水养殖系统中添加不同浓度的臭氧,研究其对循环水养殖系统生物膜活性及其净化效能的影响.结果显示,当氧化还原电位(ORP)小于450 mV时,氨氮的去除率随着臭氧浓度升高而升高,最高去除率达39.9％,亚硝酸盐氮的平均去除率为28.2％,生物膜菌群的平均存活率为88.1％,生物膜对养殖水体氨氮和亚硝酸盐氮的处理效果良好;当氧化还原电位为500 mV时,经过臭氧24 h处理,氨氮和亚硝酸盐氮的去除率分别由36.5％、28.1％降到12.2％、8.4％,而臭氧4h处理后,生物膜对氨氮和亚硝酸盐氮的去除率分别由47.5％、32.1％降到5.0％、3.3％,水处理效果明显下降,生物膜菌群存活率由88.1％降到31.5％.由此可见臭氧添加浓度对生物膜及净化效能有重大影响.综合试验结果和分析评估,建议封闭循环水养殖系统的臭氧添加量以控制生物滤池内的氧化还原电位低于400 mV为宜,可保证循环水系统的安全性和经济性.     

Effects of ozone on major antioxidants and microbial populations of fresh-cut papaya

The problems that are usually associated with fresh-cut commodities are the rapid depletion of nutritional value and the presence of high microbial populations. Ozone is a strong oxidant that can elicit physiological, chemical and microbial changes in fresh produce. Therefore, fresh-cut papaya was treated with ozone (9.2 ± 0.2 μl/L) at 10, 20 and 30 min to investigate its effect on phytochemicals and microbial load. Following a 20 min ozone treatment, the total phenolic content of fresh-cut papaya increased by 10.3% while the ascorbic acid content decreased by 2.3% compared to that of untreated control fruit. Also, gaseous ozone reduced microbial counts being more effective on coliforms (0.39–1.12 log 10 CFU/g) than on mesophilic (0.22–0.33 log 10 CFU/g) bacteria. The results suggest that microbial populations on fresh-cut papaya can be reduced without depleting its major antioxidants except for ascorbic acid when subjected to 9.2 ± 0.2 μl/L gaseous ozone for 20 min.