Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón- IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain.
Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón- IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain.
Food Microbiol. 2019 Dec;84:103246. doi: 10.1016/j.fm.2019.103246. Epub 2019 Jun 19.
Traditional and novel technologies for food preservation are being investigated to obtain safer products and fulfil consumer demands for less processed foods. These technologies inactivate microorganisms present in foods through their action on different cellular targets, but the final cause of cell loss of viability often remains not well characterized. The main objective of this work was to study and compare cellular events that could play a role on E. coli inactivation upon exposure to treatments with technologies of different nature. E. coli cells were exposed to heat, high hydrostatic pressure (HHP), pulsed electric fields (PEF) and acid treatments, and the occurrence of several alterations, including presence of sublethal injury, membrane permeabilization, increased levels of reactive oxygen species (ROS), DNA damage and protein damage were studied. Results reflected differences among the relevance of the several cellular events depending on the agent applied. Sublethally injured cells appeared after all the treatments. Cells consistently recovered in a higher percentage in non-selective medium, particularly in minimal medium, as compared to selective medium; however this effect was less relevant in PEF-treated cells. Increased levels of ROS were detected inside cells after all the treatments, although their order of appearance and relationship with membrane permeabilization varied depending on the technology. A high degree of membrane permeabilization was observed in PEF treated cells, DNA damage appeared as an important target in acid treatment, and protein damage, in HHP treated cells. Results obtained help to understand the mode of action of food preservation technologies on bacterial cells.
传统和新颖的食品保鲜技术正在被研究，以获得更安全的产品，并满足消费者对低加工食品的需求。这些技术通过作用于不同的细胞靶点来使食品中的微生物失活，但细胞丧失活力的最终原因往往还没有很好地描述。这项工作的主要目的是研究和比较在不同性质的技术处理下，可能对大肠杆菌失活起作用的细胞事件。将大肠杆菌细胞暴露于热、高静压（HHP）、脉冲电场（PEF）和酸处理中，并研究了几种改变的发生，包括亚致死损伤的存在、膜通透性增加、活性氧（ROS）水平升高、DNA 损伤和蛋白质损伤。结果反映了根据所应用的试剂，几种细胞事件的相关性的差异。所有处理后都出现了亚致死损伤的细胞。与选择性培养基相比，非选择性培养基中细胞的恢复百分比更高，特别是在基本培养基中，但在 PEF 处理的细胞中，这种效果不那么显著。所有处理后，细胞内均检测到 ROS 水平升高，尽管其出现顺序和与膜通透性的关系因技术而异。PEF 处理的细胞中观察到高度的膜通透性，酸处理中 DNA 损伤是一个重要的靶点，HHP 处理的细胞中蛋白质损伤。获得的结果有助于了解食品保鲜技术对细菌细胞的作用模式。
