Inactivation of Single Strains of Listeria monocytogenes and Salmonella Typhimurium Planktonic Cells Biofilms With Plasma Activated Liquids
Inactivation of Single Strains of Listeria monocytogenes and Salmonella Typhimurium Planktonic Cells Biofilms With Plasma Activated Liquids
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DOI：
10.3389/fmicb.2019.01539
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发表时间：
2019-07-04
影响因子：
5.2
通讯作者：
Van Impe, Jan F.
中科院分区：
文献类型：
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作者：
Smet, Cindy;Govaert, Marlies;Van Impe, Jan F.
最近的研究证明了冷大气等离子体 (CAP) 确保食品安全的能力。一种更灵活、更便于运输的替代方案是使用等离子体激活液体 (PAL)，众所周知，它也具有抗菌特性。然而，在食品安全方面，人们对其净化潜力知之甚少。因此，本研究的重点是确定 (i) 微生物种类及其细胞类型（浮游细胞或生物膜）、(ii) CAP 设置（即气体成分和生成时间）和 (iii) PAL 相关因素（处理时间和 PAL 年龄）对技术功效的影响。使用平板计数技术监测细胞密度，并通过预测失活模型分析结果。此外，还测量了长寿命物质（即过氧化氢、亚硝酸盐和硝酸盐）的 pH 值和浓度，以表征 PAL 溶液。结果表明，虽然病原体类型影响治疗效果，但主要是细胞模式具有重要影响。工作气体中氧气的存在确保了具有更高抗菌活性的 PAL 溶液的生成。此外，为了确保良好的微生物灭活，PAL 生成时间需要足够长。两种 CAP 相关因素都会导致长寿物种数量增加，从而增强灭活能力。 30分钟。使用 O-2 生成 PAL，这导致生物膜的对数减少高达 3.9，浮游细胞的对数减少高达 5.8。然而，储存溶液中 PAL 活性的丧失，以及灭活动力学中频繁出现的拖尾相，暗示了所产生的短寿命物种的重要性。与 (i) 病原体及其细胞模式、(ii) CAP 设置和 (iii) PAL 相关因素相关的不同因素已被证明会影响解决方案的抗菌功效，应在 PAL 技术的未来应用中予以考虑。
Recent research has proven the ability of cold atmospheric plasma (CAP) for assuring food safety. A more flexible and transportable alternative is the use of plasma activated liquids (PAL), which are also known to have antimicrobial properties. However, within the context of food safety, little is known on its potential regarding decontamination. This research therefore focusses on identifying the impact of (i) the microbial species and its cell type (planktonic cells or biofilms), (ii) the CAP settings (i.e., gas composition and generation time) and (iii) PAL related factors (treatment time and PAL age) on the technologies efficacy. Cell densities were monitored using the plate counting technique for which the results were analyzed by means of predictive inactivation models. Moreover, the pH and the concentrations of long-lived species (i.e., hydrogen peroxide, nitrite, and nitrate) were measured to characterize the PAL solutions. The results indicated that although the type of pathogen impacted the efficacy of the treatment, mainly the cell mode had an important effect. The presence of oxygen in the operating gas ensured the generation of PAL solutions with a higher antimicrobial activity. Moreover, to ensure a good microbial inactivation, PAL generation times needed to be sufficiently long. Both CAP related factors resulted in a higher amount of long-lived species, enhancing the inactivation. For 30 min. PAL generation using O-2, this resulted in log reductions up to 3.9 for biofilms or 5.8 for planktonic cells. However, loss of the PAL activity for stored solutions, together with the frequent appearance of a tailing phase in the inactivation kinetics, hinted at the importance of the short-lived species generated. Different factors, related to (i) the pathogen and its cell mode, (ii) the CAP settings and (iii) PAL related factors, proved to impact the antimicrobial efficacy of the solutions and should be considered with respect to future applications of the PAL technology.