Sterilization of Staphylococcus Aureus by an Atmospheric Non-Thermal Plasma Jet

An atmospheric non-thermal plasma jet was developed for sterilizing the Staphylococcus aureus （S. aureus）. The plasma jet was generated by dielectric barrier discharge （DBD）, which was characterized by electrical and optical diagnostics. The survival curves of the bacteria showed that the plasma jet could effectively inactivate 10 6 cells of S. aureus within 120 seconds and the sterilizing efficiency depended critically on the discharge parameter of the applied voltage. It was further confirmed by scanning electron microscopy （SEM） that the cell morphology was seriously damaged by the plasma treatment. The plasma sterilization mechanism of S. aureus was attributed to the active species of OH, N 2 ＋ and O, which were generated abundantly in the plasma jet and characterized by OES. Our findings suggest a convenient and low-cost way for sterilization and inactivation of bacteria.

Development of a new atmospheric pressure cold plasma jet generator and application in sterilization

This paper reports that a new plasma generator at atmospheric pressure, which is composed of two homocentric cylindrical all-metal tubes, successfully generates a cold plasma jet. The inside tube electrode is connected to ground, the outside tube electrode is connected to a high-voltage power supply, and a dielectric layer is covered on the outside tube electrode. When the reactor is operated by low-frequency （6 kHz-20 kHz） AC supply in atmospheric pressure and argon is steadily fed as a discharge gas through inside tube electrode, a cold plasma jet is blown out into air and the plasma gas temperature is only 25-30℃. The electric character of the discharge is studied by using digital real-time oscilloscope （TDS 200-Series）, and the discharge is capacitive. Preliminary results are presented on the decontamination of E.colis bacteria and Bacillus subtilis bacteria by this plasma jet, and an optical emission analysis of the plasma jet is presented in this paper. The ozone concentration generated by the plasma jet is 1.0× 10^16cm^-3 which is acquired by using the ultraviolet absorption spectroscopy.

Sterilization of Turmeric by Atmospheric Pressure Dielectric Barrier Discharge Plasma

In this study atmospheric pressure dielectric barrier discharge （DBD） plasma has been employed for sterilizing dry turmeric powders. A 6 kV, 6 kHz frequency generator was used to generate plasma with Ar, Ar/Ou, He, and He/O2 gases between the 5 mm gap of two quartz covered electrodes. The complete sterilization time of samples due to plasma treatment was measured. The most important contaminant of turmeric is bacillus subtilis. The results show that the shortest sterilization time of 15 rain is achieved by exposing the samples to Ar/O2 plasma. Survival curves of samples are exponential functions of time and the addition of oxygen to plasma leads to a significant increase of the absolute value of time constant of the curves. Magnitudes of protein and DNA in treated samples were increased to a similar value for all samples. Taste, color, and solubility of samples were not changed after the plasma treatment.

Sterilization of mycete attached on the unearthed silk fabrics by an atmospheric pressure plasma jet

The sterilization of the simulated unearthed silk fabrics using an atmospheric pressure plasma jet（APPJ） system employing Ar/O2 or He/O2 plasma to inactivate the mycete attached on the silk fabrics is reported. The effects of the APPJ characteristics（particularly the gas type and discharge power） on the fabric strength, physical-chemical structures,and sterilizing efficiency were investigated. Experimental results showed that the Ar/O2 APPJ plasma can inactivate the mycete completely within 4.0 min under a discharge power of 50.0 W. Such an APPJ treatment had negligible impact on the mechanical strength of the fabric and the surface chemical characteristics. Moreover, the Ar ions, O and OH radicals were shown to play important roles on the sterilization of the mycete attached on the unearthed silk fabrics.

Comparison of Sterilizing Effect of Nonequilibrium Atmospheric-Pressure He/O_2 and Ar/O_2 Plasma Jets

The sterilizing effect of the non-equilibrium atmospheric pressure plasma jet by applying it to the Bacillus subtilis spores is invesigated. A stable glow discharge in argon or helium gas fed with active gas （oxygen）, was generated in the coaxial cylindrical reactor powered by the radio-frequency power supply at atmospheric pressure. The experimental results indicated that the efficiency of killing spores by making use of an Ar/O2 plasma jet was much better than with a He/O2 plasma jet. The decimal reduction value of Ar/O2 and He/O2 plasma jets under the same experimental conditions was 4.5 seconds and 125 seconds, respectively. It was found that there exists an optimum oxygen concentration for a certain input power, at which the sterilization efficiency reaches a maximum value. It is believed that the oxygen radicals are generated most efficiently under this optimum condition.

Realizing high efficiency and large-area sterilization by a rotating plasma jet device

By tilting a plasma jet and rotating 360°,a large-area can be scanned and sterilized in a short time.Compared with the previous array device,this pipe has the significant advantages of high sterilization uniformity and low gas consumption.Firstly,a rotatable plasma jet device,which can control the swing and rotation of a jet pipe,is designed,and a corresponding theoretical model is established to guide the experiment.Secondly,with Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli)as the target bacteria,the device achieves a short sterilization time of 158 s—the minimum sterilization flow of S.aureus and E.coli is 0.8 slm and 0.6 slm,respectively.The device is compared with an array plasma sterilization device in terms of sterilization speed and gas consumption.The results show that the device is not only better than an array plasma sterilization device with respect to scanning uniformity,but also far less than the array plasma sterilization device in gas consumption of 5 slm.Therefore,the device has great potential in applications involving efficient,large-area sterilization.

纸质档案消毒与霉菌灭活的方法综述

纸质档案霉菌滋生的破坏性不可小觑,不但会损坏纸质档案原件而影响档案利用,而且会严重威胁档案管理人员身体健康,因此对纸质档案进行消毒与灭菌至关重要。通过简单解析纸质档案霉菌滋生条件与危害,详细阐述了低氧气调消毒灭菌法、冷冻臭氧消毒灭菌法、等离子臭氧消毒灭菌法、环氧乙烷熏蒸消毒灭菌法、γ射线辐照消毒灭菌法等不同纸质档案消毒与霉菌灭活方法的原理、技术特点以及灭菌效果。而不同方法各具优势与不足,需针对不同纸质档案霉菌情况与消毒灭活需求选择切实可行且行之有效的方法。

大气压等离子体射流在环境领域的应用进展

大气压等离子体射流(APPJ)是一种新兴的大气压等离子体放电技术,其在大气压下产生,具有放电温度和激发电压低、放电装置灵活、操作简便安全等优点,能够在大气环境中产生,在生物医学、环境卫生、材料改性等多领域具有广泛的应用前景。概述了近年来国内外APPJ在环境卫生和环境污染治理等环境领域,特别是环境灭菌、环境污染物去除和环境藻类治理等方面的应用;阐述了APPJ的射流装置与处理方式、效果和机理;基于研究现状,探讨了APPJ在环境领域应用存在的问题与解决途径,主要包括其灭菌降解机理、试验规模放大、等离子体射流发生装置设计和等离子体射流电源研发;最后展望了该技术未来在环境领域应用的发展方向和趋势。

不同灭菌工艺对香菇培养料理化特性与微生物菌群动态变化的影响

为探究不同灭菌工艺对香菇生长发育的影响,本研究采用Illumina MiSeq高通量测序技术和理化特性检测方法,对不同灭菌工艺(常压灭菌C、微压灭菌Z和高压灭菌G)条件下的培养料理化特性变化、微生物群落结构和多样性以及香菇生长发育情况进行系统分析。结果表明,G工艺和Z工艺的菌棒成品率和菌丝生长速度均高于C工艺,分别为98.98%、97.08%和3.27、3.69 mm·d^(-1);C工艺和Z工艺的产量均高于G工艺,分别为0.61和0.59 kg/棒。C工艺含水量、碳氮比在灭菌后高于G工艺和Z工艺,而木质纤维素含量则低于G工艺和Z工艺。在灭菌后至采收期,G工艺的纤维素和半纤维素降解能力强,Z工艺的纤维素降解能力强,而C工艺则是木质素的降解能力强。C工艺中丰度最高的优势菌群是醋酸杆菌科未知属(Acetobacteraceae_unclassified),G工艺和Z工艺中丰度最高的优势菌群是伯克氏菌科未知属(Burkholderiaceae_unclassified)。结合SparCC相关分析结果表明,Z工艺中丰度排名前16的优势菌群丰度与木质素和纤维素含量的相关性较高。相关性网络图显示,Z工艺具有更复杂的连接,与微生物之间的正向关系比例较高。综上所述,微压灭菌(Z)工艺能够创造更好的微生物环境并获得较高的纤维素降解率,能更好地保证香菇的产量和菌棒成品率。本研究结果为香菇的精准化栽培提供了技术支撑。

冷等离子体结合气调包装对杨梅贮藏品质的影响

以云南东魁鲜杨梅为试验材料,以未进行冷等离子体处理和气调包装处理的杨梅果实为对照,分别采用单独冷等离子体、单独气调包装及冷等离子体结合气调对杨梅进行处理,探究冷等离子体结合气调包装处理对杨梅贮藏品质的影响。结果表明:冷等离子体结合气调包装处理可显著降低杨梅果实初始菌落数,贮藏期间能较好地抑制菌落总数的增长,对杨梅色泽无明显影响,能显著延缓可溶性固形物含量的下降,保持较高的好果率;其还可抑制杨梅超氧化物歧化酶(SOD)活性的下降,延缓果实的氧化损伤和品质劣变;冷等离子体结合气调包装处理时,冷等离子体处理时间越长,保鲜效果越好。该研究可为杨梅的贮藏保鲜提供理论参考。

大气压低温等离子体对采后桑椹大肠埃希菌的杀灭作用

食品表面的大肠埃希菌(Escherichia coli)对消费者的健康构成威胁,而大气压低温等离子体技术(cold atmospheric plasma,CAP)作为一种新兴的非热杀菌技术,已在食品杀菌保鲜领域得到广泛应用。为探究CAP对E.coli的杀灭作用及机制,文中以采后桑椹表面E.coli为试验菌株,研究了CAP对E.coli的抑制效果及对其细胞膜、亚显微结构、胞内活性氧(reactive oxygen species,ROS)积累和细胞凋亡情况的影响,探讨了CAP技术对E.coli的杀菌机制。结果表明,CAP处理可显著抑制E.coli的生长,造成其细胞膜破损及部分细胞裂解,同时引起E.coli细胞内ROS的积累,进一步诱导其发生细胞凋亡,E.coli细胞受损程度、ROS积累趋势和凋亡率均随电流强度增加而增加。由此推测,CAP可能通过对E.coli细胞膜的损伤引起胞内生物学损伤,破坏细胞活性,从而对其起到抑制和杀灭效果。

大气压冷等离子体在即食肉制品中的应用研究进展

即食肉制品在加工、运输、贮藏和销售等环节极易污染细菌、酵母菌和霉菌,造成腐败变质并引发食源性疾病。大气压冷等离子体(Atmospheric cold plasma,ACP)是一种新型非热加工技术,具有杀菌效果好、处理温度低且对食品营养和感官影响小等优点,在食品杀菌保鲜领域具有广阔的应用前景。本文概述了ACP对微生物的杀灭作用和影响因素,介绍了ACP在即食肉制品杀菌保鲜中的应用研究进展,并探讨了ACP处理对即食肉制品中脂质、蛋白质、色泽及感官品质等指标的影响,以期为ACP在即食肉制品杀菌保鲜中的实际应用提供参考。

Role of anthropogenic forcing and atmospheric circulation in a lowtemperature event in February 2022 in eastern China

In February 2022,eastern China experienced prolonged low temperatures,with significant impacts on agriculture,transportation,and power supply.The regional average temperature anomaly for February 2022 was-0.65℃,making it the third coldest February from 2000 to 2022.Understanding the influence of anthropogenic forcing and atmospheric circulation on low-temperature events is important for climate change adaptation and mitigation in the region.This study used observational and model data from the Coupled Model Intercomparison Project Phase 6 to conduct an extreme event attribution study.The results showed that anthropogenic forcing led to a 1.5-fold decrease in the probability of 2022-like events,with anthropogenic greenhouse gases being the primary contributors to this reduction.Conversely,aerosols slightly increased the likelihood of such events.To evaluate the role of atmospheric circulation in this event,we chose Siberian High as the key circulation system and employed circulation similarity,intensity classification,and regression methods to estimate the impacts of circulation patterns,circulation in-tensity,and human-induced circulation change.The results demonstrated that under the influence of the same anthropogenic forcing,the presence of an anomalous Siberian High and anomalously enhanced intensity of the Siberian High both increased the likelihood of such a cold event occurrence.However,anthropogenic forcing exerts a negligible effect on such cold events via anomalous circulation.

两种大气压等离子体处理大肠杆菌的实验研究

为验证等离子体对大肠杆菌的杀灭效果并探讨其灭菌机理,进行了大气压下同轴介质阻挡放电射流装置和APMTP+JET型微波等离子体源两种等离子体发生装置激发等离子体的灭菌实验,并由活菌计数分别得出大肠杆菌存活曲线,通过扫描电镜对比灭菌实验前后大肠杆菌的状态,以对大气压等离子体灭菌机理进行初步分析。实验证明,该微波等离子体灭菌效果远好于同轴介质阻挡放电等离子体射流;两种装置对大肠杆菌的杀灭过程呈不同变化趋势;推测灭菌作用的主导因素为活性基团和高能粒子,其中静电电荷积累有一定作用。对于APMTP+JET装置微波等离子体,热效应不可忽略,其他因素则协同灭菌。

等离子体表面处理与大气压下的辉光放电

与传统的方法相比,等离子体处理的高效、无毒、节能特性使得它在表面处理和灭菌消毒方面有着很好的应用前景,在上述工业领域,“经典”的大气压放电诸如电晕放电、介质阻挡放电以及电弧放电都不适用。然而,尽管低气压下的辉光放电已得到了很好的发展,大气压下辉光放电的实现还存在一些困难。目前,对大气压下辉光放电物理过程的探索集中在其物理机制、图像捕获以及大气压下空气中辉光放电的实现方面。

联合冷杀菌技术的研究进展

本文对目前国内外研究报道的一些适合于固体食品的联合冷杀菌技术进行了综述。主要包括超声波、辐照、超高压、气调等技术相互联合杀菌,在降低各单一冷杀菌技术作用强度和成本的同时,提高杀菌灭酶效果。

大气压等离子体射流灭菌的研究进展

大气压等离子体射流是一种新兴的灭菌技术,其在大气压下产生,射流气体温度低、化学活性高,具有快速、安全、有效地杀灭微生物的特点,在生物医学、环境卫生等多领域具有广泛的应用前景。本文综述了大气压等离子体射流灭菌的作用机理、影响因素及其在生物医学和环境卫生等方面的应用现状,并展望了该技术未来的发展方向。

不同杀菌方式对手抓羊肉挥发性风味物质的影响

以宁夏特色小吃手抓羊肉为对象,采用顶空固相微萃取(SPME)和气相色谱-质谱法(GC-MS)检测手抓羊肉中挥发性风味物质的种类和含量,并进行主成分分析和聚类分析。结果表明:未杀菌、常压低温杀菌和高温高压杀菌处理的手抓羊肉制品分别检测出48,47,51种挥发性风味物质;主成分分析可得常压低温杀菌组得分最高,其中酸类、醇类、杂环类是相关性最高的3类特征性挥发性物质,高温高压组得分最低。聚类分析可将对照组和常压低温杀菌组聚为一类,高温高压杀菌组自为一类;当标度为5时,可将8类挥发性成分聚为两类,即酸类、酮类、醚类、醇类、醛类、酯类、杂环类聚为一类,烃类自为一类。

不同杀菌方式对软质胶原蛋白冻品质及抗氧化活性的影响

以猪皮胶原蛋白酶解液为主要原料,经热诱导凝胶制成软质胶原蛋白冻,系统研究不同的杀菌方式(巴氏杀菌、常压沸水杀菌、高压蒸汽杀菌)对其品质及抗氧化特性的影响。研究结果表明,高压蒸汽杀菌后软质胶原蛋白冻的色泽变黄,硬度、弹性和咀嚼性都明显下降(p<0.05)。不同杀菌方式处理后,经超滤分离的四个组分(>50、10~50、5~10、<5 k Da)中,分子量>50 k Da的蛋白质组分所占比例最大,常压沸水杀菌组中分子量为5~10 k Da和<5 k Da的组分比例最大,分别为25.71%和9.48%。常压沸水杀菌后软质胶原蛋白冻的DPPH自由基和羟基自由基的清除能力最强,其IC50分别为0.042 g/m L和0.093 g/m L,且色泽明亮且弹性较好。常压沸水杀菌不仅有良好的杀菌效果,还能较好的保持软质胶原蛋白冻的质构特性和抗氧化活性,这为新型软质胶原蛋白的冻加工技术奠定基础。

生鲜面保鲜技术的研究进展

简述了生鲜面的产品特点,重点针对生鲜面的保鲜问题,介绍了现有的常规保鲜方法,并探讨了一些适合生鲜面特点的新型保鲜方法,为开发行之有效的保鲜工艺提供参考,以期促进生鲜面在国内外市场的成熟。