Microbial decontamination by means of cold atmospheric plasma (CAP) offers great potential for treatment of heat-sensitive food products, extending their storage life. CAP is created by applying a high voltage to a gas stream, resulting in microbial inactivation according to different mechanisms. This paper thoroughly assesses the influence of CAP on the storage life of food model systems inoculated with Salmonella Typhimurium. (Food) model systems, with varying intrinsic factors (pH, salt concentration, and food (micro)structure), are treated for 5 min using a dielectric barrier discharge reactor generating a helium‑oxygen plasma. Following treatment, the impact of extrinsic factors is evaluated by storage at 8 °C or 20 °C. During storage, cell densities are determined. Data are fitted with predictive (growth or inactivation) models. As additional experiments indicate that the CAP treatment itself has a limited or even negligible effect on the properties of the model system (pH, a_w, (micro)structure), the microbial behavior of CAP treated samples during storage can be attributed to the treatment. CAP treatment can result in microbial reductions up to 2.7 log₁₀ and prolongs storage, however its rate of success is dependent on both extrinsic and intrinsic factors. An important factor is the storage temperature, as recovery of CAP treated cells proves more difficult when stored at 8 °C. At 20 °C, cell growth is merely slowed down. Additionally, at pH 5.5, 6% (w/v) NaCl, osmotic stress is induced on the microorganisms, which results in low cell recovery or further inactivation. The influence of the food (model) structure on the storage behavior is insignificant.

Industrial relevance

Although being a very promising technology, most studies regarding the use of cold atmospheric plasma (CAP) for food decontamination focus on the inactivation of a target microorganism, in relation to a specific food product. Fundamental knowledge on this non-thermal technology, including its impact on the storage life, is lacking. This study investigates the effect of CAP on the microbial behavior during storage. By performing tests on model systems, for a variation of intrinsic and extrinsic factors, this work renders information on the suitability of this novel technology regarding treatment of a broad spectrum of food products. Moreover, this study demonstrates the limited impact of CAP on the food (model) properties, enhancing the suitability of the technology to be implemented in the food industry.

中文翻译：

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低温大气血浆，内在和外在因素对（食品）模型系统在储存过程中微生物行为的综合影响

通过冷大气等离子体（CAP）进行的微生物净化为热敏感食品的处理提供了巨大潜力，从而延长了它们的存储寿命。通过向气流施加高压来产生CAP，根据不同的机理导致微生物失活。本文全面评估了CAP对沙门氏菌接种的食品模型系统保质期的影响。鼠伤寒。使用产生氦氧等离子体的介电势垒放电反应器，将具有不同内在因素（pH，盐浓度和食物（微）结构）的（食物）模型系统处理5分钟。处理后，通过在8°C或20°C下存储来评估外部因素的影响。在储存期间，确定细胞密度。数据符合预测（增长或失活）模型。由于其他实验表明CAP处理本身对模型系统的特性（pH，_w，（微）结构）的影响有限，甚至可以忽略不计，因此在存储过程中CAP处理的样品的微生物行为可以归因于处理。CAP治疗可导致微生物减少多达2.7 log ₁₀并延长储存时间，但是其成功率取决于外部因素和内在因素。一个重要的因素是储存温度，因为在8°C下储存时，经CAP处理的细胞的回收更加困难。在20°C时，细胞生长只会减慢。此外，在pH 5.5、6％（w / v）NaCl的条件下，对微生物产生了渗透压，导致细胞回收率低或进一步失活。食物（模型）结构对存储行为的影响微不足道。

行业相关性

尽管这是一项非常有前途的技术，但有关使用冷大气等离子体（CAP）进行食品净化的大多数研究都集中于特定微生物产品的目标微生物的灭活。缺乏关于这种非热技术的基础知识，包括其对存储寿命的影响。这项研究调查了CAP对储存过程中微生物行为的影响。通过对模型系统进行测试，以了解内在和外在因素的变化，这项工作提供了有关这种新颖技术在处理各种食品方面的适用性的信息。此外，这项研究表明CAP对食品（模型）特性的影响有限，从而增强了在食品工业中实施该技术的适用性。