IN VITRO AND MICROSCOPIC ANALYSIS OF OZONE FUMIGATION EFFECTS ON SALMONELLA TYPHIMURIUM AND LISTERIA MONOCYTOGENES

Objective of this study is to evaluate the effects of ozone (O₃) fumigation including ozone concentrations (0.1, 0.5 and 1.0 ppm) and exposure times (2, 6 and 18 hours) on in vitro population of foodborne pathogens; S. typhimurium and L. monocytogenes. Both main factors; ozone concentrations and exposure times as well as their interaction have significant (P<0.05) effects on the bacterial population. Optimal reduction was achieved from exposure to 0.5 ppm of ozone for 2 hours where 92.3 and 99.97% of the respective pathogens were destroyed. No significant reductions (P<0.05) were achieved as concentration and time were further increased. Our results also showed that S. typhimurium has higher resistance towards ozone compared to L. monocytogenes. The variability in the resistance response towards ozone may be due to differences in cell wall type and degree of peptidoglycan cross-linking. The destruction effects of ozone on bacterial cells were proven in ESEM analysis.