Roohi Reza, Hashemi Seyed Mohammad Bagher, Zarrinpour Balaei Mohammad Reza
Department of Mechanical Engineering, Faculty of Engineering, Fasa University, Fasa, Iran.
Department of Food Science and Technology, Faculty of Agriculture, Fasa University, Fasa 74616-86131, Iran.
Ultrason Sonochem. 2025 Jan;112:107161. doi: 10.1016/j.ultsonch.2024.107161. Epub 2024 Nov 26.
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.
本研究旨在探究热超声处理（TS；37千赫兹，300瓦；30、40、50和60℃处理10分钟）和NaCl（12% w/v）对生菜中金黄色葡萄球菌和福氏志贺菌的灭活效果，同时研究灭活动力学及该过程的热力学行为。采用计算流体动力学（CFD）模拟分析声压场、速度等值线和流线。结果表明，与TS以及NaCl + TS联合处理相比，添加NaCl对灭活的影响最小。温度升高导致两种细菌的灭活率更高，在60℃时效果更显著。与添加NaCl相比，热超声处理对灭活的影响更一致。在30℃和60℃温度水平下，经热超声处理后，金黄色葡萄球菌和福氏志贺菌的数量分别可减少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著关系。仅用NaCl处理的样品比其他样品具有更高的能量吸收。
