College of Food Science and Engineering, and Shandong Reseach Center for Meat Food Quality Control, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China.
Nanjing Innovation Center of Meat Products Processing, and College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China.
Food Res Int. 2020 Mar;129:108887. doi: 10.1016/j.foodres.2019.108887. Epub 2019 Dec 6.
In the present study, the action mechanism of ultrasound (US) combined with sodium hypochlorite (SH) against Escherichia coli was illustrated by different analysis, including reduction, particle size distribution, scanning electron microscopy (SEM), transmission electron microscopy (TEM), K leakage, confocal laser scanning microscopy (CLSM) and fluorescence spectroscopy of Escherichia coli. The results showed that ultrasound improved the antimicrobial effect of SH in control of E. coli. No significant difference was obtained in reduction of E. coli, CLSM analysis and K leakage between US + SH (US + 30 ppm SH) and SH (50 ppm SH) treatment. Smaller particle size was recorded in US and US + SH treatment. The changes of morphology and intracellular organization of E. coli cells as a result of these treatments were confirmed by SEM and TEM analyses. Fluorescence spectroscopy results indicated SH, US + SH and SH treatment caused the burial of tyrosine residues and tryptophan residues as well as increase of hydrophobicity. Therefore, the mechanism of US + SH treatment against E. coli involved decreased particle size, damaged membrane and changes of intracellular organization and protein conformation.
在本研究中，通过还原分析、粒径分布分析、扫描电子显微镜（SEM）分析、透射电子显微镜（TEM）分析、K 渗漏分析、共聚焦激光扫描显微镜（CLSM）分析和荧光光谱分析等不同分析方法，阐述了超声（US）联合次氯酸钠（SH）对大肠杆菌的作用机制。结果表明，超声增强了 SH 对大肠杆菌的抑菌效果。US+SH（US+30ppm SH）与 SH（50ppm SH）处理组在还原、CLSM 分析和 K 渗漏方面无显著差异。US 和 US+SH 处理组记录到更小的粒径。SEM 和 TEM 分析证实了这些处理导致大肠杆菌细胞形态和细胞内组织发生变化。荧光光谱结果表明，SH、US+SH 和 SH 处理导致酪氨酸残基和色氨酸残基的埋藏以及疏水性的增加。因此，US+SH 处理大肠杆菌的机制涉及粒径减小、膜损伤以及细胞内组织和蛋白质构象的变化。
