Antimicrobial effects of essential oils on growth of bacteria, yeasts and molds

Abstract

Bacteriostatic and bactericidal effects of five essential oils (oregano, rosemary, sage, fennel and savory) were investigated on bacteria, yeasts and molds using the broth microdilution method with essential oil concentrations from 0.025 to 5.0 % (v/v) in combination with spectropho-tometry. Oregano essential oil was effective against all tested microbial strains with bactericidal and fungicidal concentrations at 0.025%. Rosemary essential oil was bactericidal on Gram-positive and Gram-negative bacteria at 0.1 and 0.3 % respectively. Fennel essential oil concentration at 0.1 and 0.3% had bacteriostatic effect on Gram-positive bacteria and Gram-negative bacteria respectively. The highest bactericidal concentration (1.0 %) of sage essential oil was observed on Y. enterocolitica and lowest (0.05 %) on L. monocytogenes. Savory essential oil was bactericidal on Gram-negative bacteria at 0.5 %. Gram-positive bacteria were more sensitive to essential oils than Gram-negative. Bacterial strains were generally more sensitive to the essential oils than yeasts and molds. The use of essential oils as antiseptics and disinfectants could be worthwhile for cleaning, disinfection and sanitation of community places and food processing plants.