The effect of ultrasound treatment in combination with nisin on the inactivation of Listeria innocua and Escherichia coli

• DOI: 10.1016/j.ultsonch.2021.105776
• Publication Date: 2021-10-07T21:41:44Z
• Authors: Katherine M. Cost...; Eirini Velliou; Jorge Gutierrez-M...; Cindy Smet; Hani El Kadri; Jan F. Van Impe; Madeleine Bussemaker
• Keywords: Technology; POWER ULTRASOUND; Listeria; Chemistry, Multidisciplinary; ANTIMICROBIAL SUSCEPTIBILITY; QC221-246; Colony Count, Microbial; CAVITATION THRESHOLD; Inactivation; HIGH-INTENSITY ULTRASOUND; MONOCYTOGENES SCOTT-A; E; 0404 agricultural biotechnology; Ultrasound; innocua; Escherichia coli; Original Research Article; QD1-999; NONTHERMAL TECHNOLOGIES; Nisin; STAPHYLOCOCCUS-AUREUS; INERTIAL CAVITATION; Science & Technology; FLOW-CYTOMETRY; E. coli; Acoustics. Sound; Acoustics; 04 agricultural and veterinary sciences; L; STAINLESS-STEEL; Anti-Bacterial Agents; 3. Good health; Chemistry; coli; L. innocua; Physical Sciences; Hurdle technology

Ultrasound, alone or in combination with natural antimicrobials, is a novel food processing technology of interest to replace traditional decontamination methods, as it milder than classical sterilisation (heat treatment) and maintains desirable sensory characteristics. However, ultrasound efficacy can be affected by structure/composition, well the order which combined treatments are applied. More specifically, target different cell components could result enhanced inactivation if applied appropriate order. The microbial properties i.e. Gram positive/Gram negative also impact treatment efficacy. This work presents systematic study effect nisin on bacteria Listeria innocua (Gram positive) Escherichia coli negative), at range cavitation conditions (44, 500, 1000 kHz). application was varied, system structure investigated varying concentration Xanthan gum used create model systems (0 - 0.5% w/v). Microbial kinetics were monitored, advanced microscopy flow cytometry techniques utilised quantify cellular level. Ultrasound shown effective against E. 500 kHz only, L. demonstrating resistance all frequencies studied. Enhanced observed for kHz, but only when before treatment. negatively impacted attributed short-lived destabilisation outer membrane sonication, allowing penetrate cytoplasmic facilitate inactivation.