School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha 410007, China.
Int J Food Microbiol. 2023 Sep 2;400:110266. doi: 10.1016/j.ijfoodmicro.2023.110266. Epub 2023 May 26.
Ultrasound technology has been focused on due to its unique advantages in biofilm removal compared with traditional antibacterial methods. Herein, the anti-biofilm properties of low-frequency ultrasound (LFUS) were studied against Enterohemorrhagic Escherichia coli O157: H7 (E. coli O157:H7). After ultrasonication (20 kHz, 300 W) for 5 min, the removal rate of biofilm from polystyrene sheets reached up to 99.999 %. However, the bacterial cells could not be inactivated completely even extending the duration of ultrasonic irradiation to 30 min. Fortunately, this study indicated that LFUS could efficiently weaken the metabolic capacity and biofilm-forming ability of bacterial cells separated from biofilm. It could be associated with the removal of cell surface appendages and damage to cell membrane induced by mechanical vibration and acoustic cavitation. Besides, the genetic analysis proved that the transcription level of genes involved in curli formation was significantly down-regulated during ultrasonic irradiation, thus impeding the process of irreversible adhesion and cells aggregation. Finally, the actual application effect of LFUS was also evaluated in different fresh produces model. The results of this study would provide a theoretical basis for the further application of ultrasound in the food preservation.
超声技术因其在去除生物膜方面具有独特的优势而受到关注。本研究探讨了低频超声（LFUS）对产志贺毒素大肠埃希氏菌 O157：H7（E. coli O157:H7）的抗生物膜特性。经超声处理（20 kHz，300 W）5 min 后，聚苯乙烯片上生物膜的去除率高达 99.999%。然而，即使将超声辐射时间延长至 30 min，也不能完全灭活细菌细胞。幸运的是，本研究表明 LFUS 可以有效地削弱从生物膜中分离出的细菌细胞的代谢能力和生物膜形成能力。这可能与机械振动和空化引起的细胞表面附属物去除和细胞膜损伤有关。此外，基因分析证明，在超声辐射过程中，卷曲形成相关基因的转录水平显著下调，从而阻碍了不可逆附着和细胞聚集的过程。最后，还评估了 LFUS 在不同新鲜农产品模型中的实际应用效果。本研究结果为超声在食品保鲜中的进一步应用提供了理论依据。
