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Pathogenic bacteria present as contaminants in food and water, may survive during processing, grow during storage and cause spoilage of food or contamination of water leading to diseases to consumers. Hence, this research investigated the bactericidal action of gaseous ozone in both surface and aqueous exposure techniques for the elimination of Escherichia coli O157:H7. The ozone generated by Dielectric Barrier Discharge (DBD) using oxygen gas as a source of ozone. E. coli O157:H7 exposed to ozone by surface technique at concentration of 9.8 mg L-1 for 2.5-7.5 min and subsequently incubated at 35 °C for 24 h. The results showed that surface ozone treatments exhibited the most effectiveness to inactivate and cause complete reduction (100% in colony forming units (CFU) mL-1) of E. coli O157:H7 growth after exposure times used. On the other hand, aqueous ozone treatments, zero plate counts were observed of E. coli O157:H7 at ozone concentrations of 20.3 and 21.6 mg L-1 after 18 and 10 minutes, respectively. This study pointed to a good candidate for decontamination of E. coli O157:H7 in both surface and aqueous ozone treatments. Therefore, the application of ozone may be useful method for surface and aqueous sanitations to control some of E. coli O157:H7 diseases.