Zhu Xiaolin, Wang Yunhong, Peng Shurui, Zhang Jiayi, Li Hongbo, Mo Haizhen, Hu Liangbin
School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China.
School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China.
Food Microbiol. 2025 Oct;131:104796. doi: 10.1016/j.fm.2025.104796. Epub 2025 Apr 5.
Non-thermal sterilization methods are effectively in eliminating foodborne pathogens while preserving the appearance and quality of food. In this study, three physical fields, magnetic field (MF), ultrasound (US), and blue light (BL), were introduced for their efficacy in sterilizing FeSO-induced viable but non-culturable (VBNC) Listeria monocytogenes (L. monocytogenes) cells over a 4 h treatment. The Fe-MF treatment induced L. monocytogenes cells to form VBNC state, resulting in an 80.13 % reduction in culturable cells, with a 90.58 % survival rate. The ultrasound-assisted FeSO (Fe-US) treatment reduced the VBNC cell population by 52.63 %. In contrast, the blue light-assisted FeSO (Fe-BL) treatment reversed the VBNC state toward culturable state at the node of 3 h, and induced irreversible 100 % cell death at 4 h, with a 94.73 % decrease in viability and 68.2 % membrane damage. Additionally, Fe-BL treatment led to cell wrinkling and secretion aggregation. BL treatment alone compromised membrane permeability and triggered intracellular protein aggregation. Mechanistic investigations revealed that BL-assisted treatment disrupted the protective mechanism of L. monocytogenes when induced by FeSO to form VBNC state, compromised VBNC cell membranes, promoted intracellular Fe accumulation, and induced a reactive oxygen species (ROS) burst and lipid peroxidation, ultimately leading to ferroptosis. Proteomic analysis identified 240 upregulated and 376 downregulated differentially expressed proteins, highlighting significant changes in pathways related to ribosome biosynthesis (related genes rplJ and hpf significant upregulated), intracellular iron homeostasis (ctaB, hemN, and lmo2590 downregulated), cellular morphology (mreB and tagH downregulated), oxidative stress response (lmo0720 and lmo0799 downregulated), and DNA synthesis (recA, dnaD, yidC2 and fruB downregulated). In conclusion, Fe-BL treatment effectively disrupted VBNC cell membranes, induced iron homeostasis imbalance, and triggered Fenton reaction-mediated ferroptosis. These findings provide a promising non-thermal sterilization strategy for inactivating VBNC L. monocytogenes, offering potential applications in food safety.
非热杀菌方法能有效消除食源性病原体，同时保持食品的外观和品质。在本研究中，引入了三种物理场，即磁场（MF）、超声波（US）和蓝光（BL），以研究它们在4小时处理过程中对硫酸亚铁诱导形成的活的但不可培养（VBNC）的单核细胞增生李斯特菌（L. monocytogenes）细胞的杀菌效果。铁-磁场处理诱导单核细胞增生李斯特菌细胞形成VBNC状态，可培养细胞数量减少80.13%，存活率为90.58%。超声辅助硫酸亚铁（铁-超声）处理使VBNC细胞数量减少52.63%。相比之下，蓝光辅助硫酸亚铁（铁-蓝光）处理在3小时节点时使VBNC状态逆转至可培养状态，并在4小时时诱导100%不可逆细胞死亡，活力下降94.73%，膜损伤68.2%。此外，铁-蓝光处理导致细胞起皱和分泌聚集。单独的蓝光处理会损害膜通透性并引发细胞内蛋白质聚集。机制研究表明，蓝光辅助处理破坏了硫酸亚铁诱导单核细胞增生李斯特菌形成VBNC状态时的保护机制，损害了VBNC细胞膜，促进了细胞内铁积累，并诱导活性氧（ROS）爆发和脂质过氧化，最终导致铁死亡。蛋白质组学分析鉴定出240个上调和376个下调的差异表达蛋白，突出了与核糖体生物合成（相关基因rplJ和hpf显著上调）、细胞内铁稳态（ctaB、hemN和lmo2590下调）、细胞形态（mreB和tagH下调）、氧化应激反应（lmo0720和lmo0799下调）以及DNA合成（recA、dnaD、yidC2和fruB下调）相关途径的显著变化。总之，铁-蓝光处理有效破坏了VBNC细胞膜，诱导铁稳态失衡，并引发芬顿反应介导的铁死亡。这些发现为灭活VBNC单核细胞增生李斯特菌提供了一种有前景的非热杀菌策略，在食品安全方面具有潜在应用价值。
