The study aimed to investigate the effect of thermosonication (TS; 37 KHz, 300 W; 30, 40, 50, and 60 °C for 10 min) and NaCl (12 % w/v) on the inactivation of Staphylococcus aureus and Shigella flexneri in lettuce, as well as to examine the kinetics of inactivation and the thermodynamic behaviors of the process. Computational Fluid Dynamics (CFD) simulations were employed to analyze the acoustic pressure field, velocity contours, and streamlines. The results showed that NaCl addition had the least impact on inactivation compared to TS and combined NaCl + TS. Increasing the temperature led to higher inactivation of both bacteria, with a more significant effect at 60 °C. Thermosonication treatment had a more consistent effect on inactivation compared to the addition of NaCl. When exposed to thermosonication, the population of S. aureus and S. flexneri could be reduced by 5.1 to 6.9 log CFU/g and 5.5 to 7.4 log CFU/g, respectively, at temperature levels of 30 and 60 °C. Additionally, no significant relationship between entropy reduction and type of microorganisms was observed. The samples that were treated only with NaCl had higher energy absorption than the other samples.

中文翻译：

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热超声和 NaCl 对生菜中金黄色葡萄球菌和福氏志贺氏菌灭活的增效效应：声场和反应动力学的影响


该研究旨在研究热超声处理（TS;37 KHz，300 W;30、40、50 和 60 °C 10 分钟）和 NaCl （12 % w/v） 对生菜中金黄色葡萄球菌和福氏志贺氏菌失活的影响，以及检查灭活动力学和该过程的热力学行为。采用计算流体动力学 （CFD） 仿真来分析声压场、速度等值线和流线。结果表明，与 TS 和联合 NaCl + TS 相比，添加 NaCl 对灭活的影响最小。提高温度导致两种细菌的灭活率更高，在 60 °C 时效果更显着。 与添加 NaCl 相比，热超声处理对灭活的影响更一致。当暴露于热超声处理时，在 30 °C 和 60 °C 的温度水平下，金黄色葡萄球菌和福氏葡萄球菌的种群可分别降低 5.1 至 6.9 log CFU/g 和 5.5 至 7.4 log CFU/g。 此外，未观察到熵减少与微生物类型之间存在显着关系。仅用 NaCl 处理的样品比其他样品具有更高的能量吸收。