In vitro Analysis of Super Critical CO₂ Extracted Essential Oils Against the Food-borne Pathogenic Bacteria

Abstract

This study was undertaken to determine the in vitro antimicrobial activities of super critical CO₂ extracted on fifteen commercial essential oils. The antimicrobial activities of essential oils were tested against three species of food-borne pathogenic bacteria Escherichia coli (VRR1 and MTCC 40), Salmonella spp. (VRR1 and MTCC 1163) and the Staphylococcus aureus (MTCC 7443). Activities were tested using agar disk diffusion assay, minimum inhibitory concentration (MIC) and vapor phase assay. Among fifteen essential oils only three oils showed maximum activity on the bacterial strains in all the three assays. Cinnamomum. verum, Syzygium aromaticum and Rosmarinus officinalis oils showed potential activity on both Gram positive and Gram negative bacteria, MIC of these oils was <0.2 % (v/v). Among three bacteria, Staphylococcus aureus was the most sensitive to the oils. This work is useful to preselect oils for application on food as preservatives.

Key words:

• Essential oils
• antimicrobial activity
• disk diffusion
• minimum inhibitory concentration
• percentage inhibition
• vapor phase