欧姆加热(OH),一种新兴的食品加工技术,用于食品加工业,由于金黄色葡萄球菌等亚致死性病原体的恢复,引发了潜在的食品安全问题(S.金黄色葡萄球菌)。在本研究中,研究了修复过程中OH损伤的金黄色葡萄球菌对各种应激条件的敏感性和细胞相关因子的变化。结果表明,液体培养基差异(营养肉汤(NB),磷酸盐缓冲盐水(PBS),牛奶,和黄瓜汁)影响受损细胞的恢复过程。营养富集决定了细菌修复率,这些培养基的修复率为牛奶>NB>黄瓜汁>PBS。损伤细胞对各种应激源的敏感性,包括不同的酸,温度,Nisin,模拟胃液,和胆汁盐,在损伤阶段增加,随后在修复时减少。此外,细胞内ATP含量,酶活性(Na+/K+-ATP酶,Ca2+/Mg2+-ATP酶,和T-ATP酶)和离子浓度(Mg2+,K+,和Ca2+)在修复过程中逐渐增加。修复5小时后,细胞的胞内物质含量明显高于未修复的受损细菌,而一些指标(例如,Na+/K+-ATP酶,K+,和Ca2)未恢复到未处理的水平。这项研究的结果表明,OH损伤的金黄色葡萄球菌在恢复后表现出增强的抗性,可能是由于细胞结构的恢复。这些发现对优化食品储存条件和推进食品工业中的OH工艺具有启示意义。
Ohmic heating (OH), an emerging food processing technology employed in the food processing industry, raises potential food safety concerns due to the recovery of sublethally injured pathogens such as Staphylococcus aureus (S. aureus). In the present study, sensitivity to various stress conditions and the changes in cellular-related factors of OH-injured S. aureus during repair were investigated. The results indicated that liquid media differences (nutrient broth (NB), phosphate-buffered saline (PBS), milk, and cucumber juice) affected the recovery process of injured cells. Nutrient enrichment determines the bacterial repair rate, and the rates of repair for these media were milk > NB > cucumber juice > PBS. The sensitivity of injured cells to various stressors, including different acids, temperature, nisin, simulated gastric fluid, and bile salt, increased during the injury phase and subsequently diminished upon repair. Additionally, the intracellular ATP content, enzyme activities (Na+/K+-ATPase, Ca2+/Mg2+-ATPase, and T-ATPase) and ion concentrations (Mg2+, K+, and Ca2+) gradually increased during repair. After 5 h of repair, the intracellular substances content of cell\'s was significantly higher than that of the injured bacteria without repair, while some indicators (e.g., Na+/K+-ATPase, K+, and Ca2+) were not restored to the untreated level. The results of this study indicated that OH-injured S. aureus exhibited strengthened resistance post-recovery, potentially due to the restoration of cellular structures. These findings have implications for optimizing food storage conditions and advancing OH processes in the food industry.