介质阻挡放电用于细菌灭活的机理研究

为研究低温等离子体灭菌的机理,利用介质阻挡放电(DBD)低温等离子体来进行了细菌灭活实验。试验选取了两种典型细菌:革兰氏阳性的金黄色葡萄球菌和革兰氏阴性的大肠杆菌。将载有细菌悬浊液的盖玻片放置在下平板电极的中央,通过调整电源电压、气隙间距和处理时间来考察电场和等离子体对两种不同细菌的作用;利用电子透射电镜(TEM)观察了等离子体处理后的细菌细胞,以确定细胞的完整性;测量了等离子体处理后的两种细菌悬浊液中蛋白质,核酸和K+的浓度。实验结果表明:在<10s时间内金黄色葡萄球菌死亡率接近100%;<7s内,大肠杆菌死亡率接近100%,取得了良好的灭菌效果。分析认为电场作用不是细菌灭活的主要因素,而等离子体中的氧自由基可以破坏细胞壁和细胞膜,以及细胞质中的蛋白质和核酸,从而起到杀菌的效果。     

大面积常压表面等离子体快速消毒灭菌实验研究

为评价一种可触摸等离子体的消毒灭菌效果,利用自制微秒脉冲电源和等离子体反应器,产生了面积为459 cm2的常压表面介质阻挡放电(SDBD)等离子体,以琼脂平板表面的细菌为处理对象,研究了等离子体的消毒灭菌过程。研究结果表明:等离子体的灭菌过程主要发生在前5~10 s,初始细菌数量约为104 CFU时,大肠杆菌、金黄色葡萄球菌、白色葡萄球菌和铜绿假单胞菌都被杀灭2.5~2.8个对数;初始细菌数量低于600 CFU时,等离子体处理10 s后细菌被全部杀光;等离子体的消毒灭菌效率随着处理间距的增大而降低,当处理间距由1 cm增大到4 cm时,大肠杆菌的杀灭对数值由2.7下降到1.1。因此,等离子体可在10 s内快速有效的杀灭琼脂平板上的试验菌。     

介质阻挡放电和介质阻挡电晕放电灭菌效果的试验研究

应用介质阻挡放电(DBD)和介质阻挡电晕放电 (DBCD)产生的低温等离子体,对金黄色葡萄球菌和大肠杆菌进行杀灭试验的结果发现,在90s内DBD和DBCD都对金黄色葡萄球菌和大肠杆菌的杀灭对数值KL达到了5。 DBCD使两种菌株减少的速度大于DBD。DBD和DBCD都使大肠杆菌减少的速度大于金黄色葡萄球菌。     

改善厨房卫生,点燃机洗火种“小抹布,大问题!中国厨房卫生调查结果公布”

你可知道小小一块洗碗布中藏匿着多少病毒和细菌吗?《中国家庭厨房卫生调查白皮书》显示,洗碗布中单块细菌总数最高的竟高达约5000亿个,而这些洗碗布中更含有包括大肠杆菌、金黄色葡萄球菌、白色念球菌、沙门氏菌在内的19种条件致病菌。博西家用电器(中国)有限公司     

改善厨房卫生，点燃机洗火种

你可知道小小一块洗碗布中藏匿着多少病毒和细菌吗？《中国家庭厨房卫生调查白皮书》显示,洗碗布中单块细菌总数最高的竞高达约5000亿个,而这些洗碗布中更含有包括大肠杆菌、金黄色葡萄球菌、白色念球菌、沙门氏菌在内的19种条件致病菌。     

“小抹布,大问题!”点燃我国洗碗机燎原之火

几十年来,使用洗碗布一直是我国居民清洁厨房器具的主要方法。然而,小小一块洗碗布却带来了不容忽视的健康问题。据调查,洗碗布中单块细菌总数最高的竟达约5000亿个,而这些洗碗布中更含有包括大肠杆菌、金黄色葡萄球菌、白色念球菌、沙门氏菌在内的19种条件致病菌。     

Ar等离子体射流处理乙醇水溶液的放电特性及灭菌效应

乙醇是一种医疗上常用的消毒剂,理论上在Ar等离子体射流处理的水溶液中掺杂乙醇可以增强灭菌效果.通过对耐甲氧西林金黄色葡萄球菌的灭活实验,发现在被处理的水溶液中掺杂20％乙醇可使Ar射流等离子体活化水的灭菌效果提高5个数量级以上.进一步地,发现当工作气体中掺杂0.2％N2或在屏蔽罩中掺杂1％O2时,只需在被处理的水溶液中...     

低温等离子体对细菌内毒素的灭活作用

为了探索低温等离子体对细菌内毒素的灭活效果,以介质阻挡放电方法产生低温等离子体,以大肠杆菌内毒素作为处理对象,采用内毒素休克小鼠模型检测低温等离子体对大肠杆菌内毒素的灭活效果。给3个试验组每只小鼠分别腹腔注射经低温等离子体处理30 s、45 s和60 s后的大肠杆菌内毒素;阴性对照组小鼠,每只腹腔注射磷酸盐缓冲液;阳性对照组小鼠,每只腹腔注射未经低温等离子体处理的大肠杆菌内毒素。注射后观察各组小鼠存活情况,记录存活时间,并对每只小鼠进行称重,总观察时间为120 h。结果发现,阴性对照组小鼠在观察时间内无一例死亡,阳性对照组小鼠24 h的死亡率为100%,3个处理组与阳性对照组比较,小鼠平均生存时间明显延长。而且随着处理时间的延长,小鼠的平均生存时间逐渐延长,平均体重也逐渐增加。表明低温等离子体可破坏大肠杆菌内毒素的活性,且随着处理时间的延长,破坏的程度越大。     

等离子体在冰箱除菌效果的研究

在风直冷冰箱和直冷冰箱中安装等离子体除菌装置,通过除菌试验研究了等离子体对大肠杆菌、金黄色葡萄球菌的除菌率.结果表明,在冰箱冷藏室不同部位,等离子体除菌效果均达到90％以上,符合国标GB 21551.4-2010的要求.     

直流负高压静电液体灭菌技术研究

采用直流负高压处理大肠杆菌、枯草杆菌、金黄色葡萄球菌的悬浊液 ,结果表明细菌存活率随着外加电压的增大而降低。随着处理时间的增长而降低。在电极距离一定 ,处理电压为 18k V,处理时间为 40 min的条件下灭菌效果较好 ,灭菌所需最大能耗为 0 .17J/ cm3,远小于国外静电脉冲灭菌实验值 2 1～ 42 J/ cm     

Effect of short HV pulses on bacteria and fungi

The survival of three kinds of microorganisms under strong-pulse electric field conditions was investigated with a possible application of the electric pulse method for sterilization of consumable liquids. The results of the investigations of survival ratio of Gram-negative (Escherichia coli, Yersinia enterocolitica) and Gram-positive (Staphylococcus aureus, Listeria monocytogenes) bacteria and yeastlike fungi (Candida albicans) are presented. The HV pulses with peak voltage U=0 to 100 kV and rise time t_n= 0.5 to 1.2 μs were applied. The microorganisms were suspended in an NaCl solution with γ=6 to 13 mS/cm conductivity and pH=7.2. The experimental setup and the dependency of the microorganism survival ratio on the rise time, peak voltage and on the number of pulses applied, are presented. It has been found that the lethal effect on microorganisms caused by HV pulses depends on the pulse parameters as well as on the kind of microorganism being treated     

Inactivating microorganisms using a pulsed electric fieldcontinuous treatment system

High-voltage pulsed electric fields (PEFs) can be used to inactivate microorganisms in liquids. Applying PEF technology to food pasteurization is a promising nonthermal method, which may radically change food preservation processes and provide consumers with microbiologically safe, minimally processed, fresh-like products. A continuous-flow system in a laboratory-size prototype was constructed for the nonthermal pasteurization of liquid foods with PEF technology. Major components in the prototype include a high-voltage repetitive pulse generator, a coaxial liquid food treatment chamber, a fiber-optic temperature sensing instrument and a data acquisition system. Microbial inactivation tests were conducted in the continuous PEF treatment system. Repetitive high-voltage pulses with an exponential decaying waveshape were applied to the liquid food which was pumped through the treatment chamber. Test microorganisms selected for inactivation were Escherichia coli, Staphylococcus aureus and Saccharomyces cerevisiae. Over 6-order-of-magnitude reductions in the viability of selected microorganisms were achieved while the food temperature was maintained below 40°C     

大气压下低温等离子体灭菌消毒技术的研究

传统灭菌方法存在的各种弊端限制了其应用范围,为研究新的灭菌技术,能够在短时间内完成灭菌效果而又不损伤医疗器械,并且要降低对医务人员以及环境的损害,在介绍了大气压下低温等离子体灭菌消毒的优点后,设计了等离子体灭菌用高频高压电源和等离子体发生器,实现了大气压下均匀的介质阻挡放电。研究发现:纯Ar放电等离子的灭菌效果远差于φ(O2)=5%的Ar混合气体放电的灭菌效果,而且等离子体灭菌的效果与细菌的种类有关。基于实验结果以及实验所用等离子发生器的特殊结构,可知等离子体灭菌机理主要是细菌与等离子中所含的活性成分发生作用。     

Inactivation of Escherichia Coli by a Coaxial Microwave Plasma Flow

An atmospheric low-temperature plasma flow generated by a microwave discharge utilizing a coaxial cable for microwave transmission was utilized for the inactivation of a bacteria. The employed device consists of a cavity, a quartz discharge tube, a coaxial cable, a microwave power source, and a gas supply system. Using this argon plasma source, we attempted to clarify the effects of exposure temperature, exposure time, exposure distance, input power, and gas flow rate on the number of surviving cells of Escherichia coli. A log reduction number of E. coli of at least 2 (10^-2) was obtained at an exposure temperature of 353 K when the exposure time was 600 s with a gas flow rate of 5 Sl/min and an input power of 400 W. The number of surviving cells decreased with an increase of exposure time under any sterilization condition.     

高压方波脉冲电场对微生物的致死作用

研究了高压方波脉冲电场对食品中常见的腐败菌枯草芽孢杆菌 ,灰绿青霉的致死作用 ,比较了几种微生物的灭活效果 ,并以酿酒酵母为材料 ,初步探讨了杀菌机理。研究表明 :微生物的致死率随电场强度、脉宽、脉冲个数的增加而增大 ,同一灭菌条件 ,酵母菌 >大肠杆菌 >枯草芽孢杆菌 >灰绿青霉。电场作用后死亡酵母细胞表面出现凹陷 ,局部有孔洞产生。     

高压脉冲电场冲击波法的液体杀菌实验研究

为研究高压脉冲电场冲击波对液体食品杀菌以实现不破坏食品的营养结构与原有风味的食品杀菌保鲜技术,阐述了在常温条件下产生高压脉冲电场冲击波的方法及其杀菌机理,介绍了以黄酒为试验原料的杀菌实验结果以及脉冲电压幅值、电容容量和放电次数对杀菌效率的影响规律。结果表明,该法在常温条件下注入能量>12 J/mL时,能使菌落总数降低2个数量级,可杀死黄酒中>97%的细菌,而对山渣汁营养成分(维生素和氨基酸等)几乎无破坏作用。     

Energy efficiency improvement of electrical sterilization usingoscillatory waveforms from a RLC discharging circuit

This paper describes effects of pulsed HV waveforms on biological cell inactivation. A simple RLC circuit with various inductance values was employed to investigate the waveform effects on the electrical sterilization of Escherichia Coli. It has been found that the minimum value of cell survivability can be realized by choosing an appropriate inductance value, even when the initial energy stored in a capacitor is constant. In order to realize higher energy efficiency than a conventional RC discharging network, circuit parameters should be determined so that amplitude and width of each pulse becomes larger than the critical values 15 kV/cm and 50 μs, respectively     

三角孔多孔板水力空化杀灭大肠杆菌的研究

实验基于自主研发的新型多孔板水力空化空蚀反应装置,选取病原微生物中较常见的大肠杆菌为指示菌,用压力数据采集系统测定了空化空蚀工作段的压力,用琼脂平板计数法检测空化空蚀作用前后大肠杆菌的菌落数,同时用生物显微镜观察其形态变化。通过不同孔口流速、不同菌液的初始浓度和不同几何参数的多孔板对大肠杆菌进行空化空蚀实验,分析了空化数、孔口流速、大肠杆菌初始浓度、孔口数量、孔口大小和孔口排列方式对大肠杆菌杀灭率的影响,阐述了水力空化空蚀作用对大肠杆菌的杀灭机理。