Antibacterial action of ozone in liquid medium against Escherichia coli and Staphylococcus aureus

Abstract

Food and waterborne diseases (DTHAs) and healthcare-associated infections (HAIs) represent an important public health problem. Among the possible etiological agents of DTHAs and HAIs, are mainly bacteria. In this context, we can highlight some bacteria such as Escherichia coli and Staphylococcus aureus, which are also involved in the contamination of food and healthcare environments. The objective of this study was to evaluate the microbicidal potential of ozonized water against Escherichia coli and Staphylococcus aureus at different concentrations and exposure times. For this, bacterial suspensions of E. coli and S. aureus were exposed to ozone under different times (1, 2 and 5 minutes) and concentrations (50, 100 and 150 ppm). After each time of ozone application, aliquots of the inoculum were collected and seeded on specific agar and incubated at 37ºC for 24-48 hours. After the incubation time, the colony forming units (CFU) were quantified and the results displayed as mean ± standard deviation and compared using the analysis of variance test (ANOVA) with Tukey as post-test. Ozone when released in a liquid medium proved to be efficient in quantity reduction both species of bacteria tested, above all, it seems to exert greater lethality on E. coli when compared to S. aureus. The action of the gas proved to be very effective, requiring low concentrations, in addition it proved to be quite fast since even in short exposure times it was able to kill bacteria significantly, even when used at low concentrations.