Abstract This study investigated the inactivation, sublethal injury, and recovery of Escherichia coli O157:H7 cells induced by ohmic heating (OH) in phosphate buffer saline (PBS) using thin agar layer (TAL) method. The voltage gradients of OH were 10 V/cm and 5 V/cm, which required 3 min and 13 min to reach the center temperature of 72 °C, respectively. The results indicated that OH at 10 V/cm voltage gradient had a comparable inactivation effect to 5 V/cm at the end of heating process. The proportion of sublethally injured cells in the survivors increased with increasing heating time and temperature and reached a maximum (>97%) at the end of both treatments. When different liquid media, temperature, pH, and sodium chloride (NaCl) concentrations were used to study the recovery process of sublethally injured cells, limited nutrition, low temperature (4 °C), lower pH (4.0), and higher NaCl concentrations (more than 3%) significantly inhibited the recovery process. These results could provide the potential possibility to explore the combination of OH with other technologies (e.g. low temperature, low pH, and high salt) to inactivate targeted pathogens in foods.

中文翻译：

---

欧姆加热后大肠杆菌O157:H7的亚致死损伤和恢复

摘要 本研究使用薄琼脂层 (TAL) 方法研究了在磷酸盐缓冲盐水 (PBS) 中欧姆加热 (OH) 诱导的大肠杆菌 O157:H7 细胞的灭活、亚致死损伤和恢复。OH 的电压梯度为 10 V/cm 和 5 V/cm，分别需要 3 分钟和 13 分钟才能达到 72 °C 的中心温度。结果表明，10 V/cm 电压梯度下的 OH 在加热过程结束时具有与 5 V/cm 相当的失活效果。存活者中亚致死损伤细胞的比例随着加热时间和温度的增加而增加，并在两种治疗结束时达到最大值（> 97％）。当使用不同的液体培养基、温度、pH 值和氯化钠 (NaCl) 浓度来研究亚致死损伤细胞的恢复过程时，有限的营养、低温 (4 °C)、较低的 pH (4.0) 和较高的 NaCl 浓度（超过 3%）显着抑制了恢复过程。这些结果为探索 OH 与其他技术（例如低温、低 pH 和高盐）相结合以灭活食品中的目标病原体提供了潜在的可能性。