Assessment and modelling the antibacterial efficacy of vapours of cassia and clove essential oils against pathogens causing foodborne illness

Abstract The present study deals with assessment of antibacterial activity of essential oil vapours (EOV) of cassia (Cinnamomum cassia) and clove (Syzygium aromaticum) using dose-response equation, and modelling the inactivation pattern of Escherichia coli, Salmonella enterica serovar Typhi and Yersinia enterocolitica under the influence of EOVs using three-parameter Weibull model. The fitted inhibition (%) data to dose-response equation estimated 0.98 and 3.63 μL/cm3 as concentration of cassia and clove EOV that could inhibit the growth of E. coli up to 90%, whereas estimated IC90 for cassia and clove EOV against S. enterica ser. Typhi was 0.52 and 1.33 μL/cm3, respectively. However, Y. enterocolitica exhibited more sensitivity under the influence of cassia and clove EOVs with IC90 of 0.2 and 0.79 μL/cm3, respectively. The inactivation model estimated 3.1 and 4.4 h required by cassia and clove EOV for 1-log10 reduction of E. coli, respectively. Similarly, 1-log CFU reduction of Y. enterocolitica under the influence of cassia and clove EOV were estimated to be 3.6 and 5.1 h, respectively, and S. enterica ser. Typhi showed highest δ-value for both the selected EOVs. Susceptibility of the bacteria strains to the EOVs can be attributed to the antibacterial efficacy of the chemical components present.