Antibacterial activity of essential oils and their main components enhanced by atmospheric RF plasma

The antibacterial activity of low concentration clove oil, sweet basil oil, and lime oil (5–20 μl ml⁻¹) and their main components (eugenol, β-ocimene, and d-limonene) at the same concentration was enhanced by atmospheric RF plasma at 20W and 40W for 10 min to effectively control the growth of Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus on chicken egg. Number of colony germination after plasma treatment was evaluated. Results showed that growth of E. coli, S. thyphimurium, and S. aureus on eggshell mixed with clove oil (10 μl ml⁻¹) or its main component (eugenol at 5 μl ml⁻¹) was completely inhibited after using plasma treatment at 40W. Without the plasma treatment, all essential oils and all their main components at concentrations of 5–20 μl ml⁻¹ could not inhibit bacterial growth. Thus, this study has demonstrated the good potential of using atmospheric RF plasma treatment to enhance the antibacterial activity of essential oil at a relatively low concentration.