Inhibitory Activity and Mechanism of High-Voltage Prick Electric Field Against Salmonella enteritidis on Gelatin Plates and Selected Food Systems.

Abstract

The present study assesses the antibacterial effect of a high-voltage prick electric field (HVPEF) on Salmonella enteritidis on gelatin plates and selected food systems. The results showed that S. enteritidis were susceptible to HVPEF treatment, with a mortality rate of 98% on the gelatin plate at 13 kV for 15 min. The survival rate of S. enteritidis decreased linearly with time and then stabilized after a sharp decline. The morphological change and the loss of internal nucleic acids and proteins suggest that the cell membrane was damaged by HVPEF, appearing more permeable and less fluid. Compared with the untreated group, both reactive oxygen species (ROS) and malondialdehyde increased significantly in the treated groups. Flow cytometry results suggest that DNA was severely damaged, which led to cell death, as shown by the elevated levels of intracellular ROS and lipid peroxidation. The death rate of S. enteritidis on the food surface significantly rose with the increase of HVPEF intensity, reaching 91 ± 1.6% (salmon), 88.2 ± 2.2% (chicken breast), 72.9 ± 2.7% (sausage), and 66.9 ± 1.6% (steak), respectively, at 14 kV for 30 min. HVPEF resulted in no significant change in color or texture; the changes in total viable count and pH were less significant than in the untreated group. Finally, HVPEF treatment led to lower levels of total volatile base nitrogen and thiobarbituric acid reactive substances in chicken breasts, which potentially contributes to longer shelf life.