Affiliation: | aUniversité de Technologie de Compiègne, Chemical Engineering Department CNRS UMR 6067, Centre de Recherche de Royallieu, BP 20529, 60205 Compiègne, France bUniversity of Balamand, Faculty of Engineering, P.O.Box 100, Tripoli, Lebanon cInstitute of Biocolloidal Chemistry named after F.D. Ovcharenko, NAS of Ukraine, 2, blvr. Vernadskogo, Kyiv 03142, Ukraine |
Abstract: | This research employed a conductometric technique to estimate the inactivation kinetics of Escherichia coli cells in aqueous suspensions (1 wt.%) during simultaneous pulsed electric fields (PEF) and thermal treatments. The electric field strength was E = 5 kV/cm, the effective PEF treatment time tPEF was within 0–0.2 s, the pulse duration ti was 10? 3 s, the medium temperature was 30–50 °C, and the time of thermal treatment tT was within 0–7000 s. The damage of E. coli was accompanied by cell size decrease and release of intracellular components. The synergy between PEF and thermal treatments on E. coli inactivation was clearly present. The non-ionic surfactant Triton X-100 additionally improved its inactivation. The characteristic damage time followed the Arrhenius law within the temperature range 30–50 °C with activation energies W = 94 ± 2 kJ mol? 1 and W = 103 ± 5 kJ mol? 1 with and without the presence of surfactant, respectively. Relations between cell aggregation, cell ζ-potentials and presence of surfactant were analysed. |