Abstract:The antibacterial effects of thirteen plant essential oils—extracted from basil, tea tree, thyme, clove, fennel, ylang-ylang, marjoram, cinnamon, eucalyptus, coriander seed, citronella, sage, and nard—against six common harmful microorganisms in food were studied using inhibition zone, fumigation, and other in vitro antibacterial experiments. The results showed that all thirteen essential oils had an inhibitory effect on the tested bacteria, fungi, and yeasts. Among them, thyme oil and cinnamon oil exhibited the strongest but different levels of antimicrobial activity; the inhibition zone diameter was >20 mm at a volume concentration of 300 μL/L of the oils. Combinations of cinnamon oil and thyme oil at different ratios did not show strong synergistic effects. However, some of the combinations showed significant additive effects, with the optimal antimicrobial effect noted for cinnamon oil/thyme oil at 80:20 (V/V).
