Influence of diluent on antimicrobial activity of cinnamon bark essential oil vapor against Staphylococcus aureus and Salmonella enterica on a laboratory medium and beef jerky.

The influence of chemical diluents on the antimicrobial activity of plant essential oil (EO) vapors was evaluated. We first determined if vapors generated from 22 chemical diluents not containing EO had antimicrobial activities. Ethyl ether vapor retarded the growth of S. aureus. The minimal inhibitory concentrations (MICs) and the minimal lethal concentrations (MLCs) of cinnamon bark EO vapor, which was diluted in and generated from 21 diluents, against S. aureus and S. enterica were determined. Cinnamon bark EO vapor showed significantly (P ≤ 0.05) lower MICs against S. aureus when diluted in dimethyl sulfoxide (DMSO), ethanol, ethyl acetate, or jojoba oil, and against S. enterica when diluted in DMSO, ethanol, or jojoba oil, compared to those in other diluents. We compared antimicrobial activities of cinnamon bark EO vapor diluted in DMSO, ethanol, ethyl acetate, or jojoba oil against S. aureus and S. enterica on beef jerky as a food model. Antimicrobial activity was significantly (P ≤ 0.05) higher when vaporized from DMSO. These results indicate that antimicrobial activity of cinnamon bark EO vapor may vary significantly (P ≤ 0.05) depending on the type of diluent from which it is vaporized. These observations provide basic information when developing food and food-contact surface decontamination strategies using EO vapors.