Metabolome analysis shows that ultrasound enhances the lethality of chlorine dioxide against Salmonella Typhimurium by disrupting its material and energy metabolism

The physiological status of Salmonella after its ultrasonication was investigated to reveal the potential mechanism through which ultrasound enhances the lethality of chlorine dioxide against Salmonella. Applying either the probe ultrasound (US) or water bath ultrasound (WUS) disrupted the cellular structure of Salmonella bacteria, increased the permeability of their bacterial outer membrane (US: 9.00 %, WUS: 11.96 %), and caused intracellular reactive oxygen species to accumulate (US: 13.95 %, WUS: 4.34 %,), which resulted in a reduction of ATP (US: 15.22 %, WUS: 14.15 %) and ATPase activity (US: 3.13 %, WUS: 26.06 %). This series of adverse effects eventually led to the disruption of the metabolic process in Salmonella cells, by mainly altering the metabolism of lipids, small molecules, and energy. Therefore, ultrasound enhances the lethality of chlorine dioxide primarily by disrupting the cellular structure, intracellular material, and energy homeostasis of Salmonella. This finding will promote the development and application of ultrasonic-assisted sterilization technology in food industries.