Antimicrobial Activity of a Blend of Essential Oils Extracted from Oregano and Cinnamon

The antimicrobial property of essential oils extracted from oregano and cinnamon have been documented and widely reviewed. However, most of the in vitro studies determined the inhibitory activity based on a single essential oil and/or purified active compound. The aim of this study was to determine the overall inhibitory activity in terms of minimum inhibitory concentration (MIC) of a blend of oregano and cinnamon essential oils in a commercial product against pathogenic bacteria. The result showed that the blend of the essential oils inhibited Escherichia coli, Escherichia coli O157:H7, Salmonella enteritidis, Salmonella typhimurium, Vibrio cholerae, and Vibrio parahaemolyticus at MICs ranging from 31.25 to 250 mg/L. The MICs of the examined blend against Bacillus cereus, Campylobacter jejuni, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus were greater than 1,000 mg/L. This finding suggests that the examined blend of essential oils could, to some extent, inhibit Escherichia coli, Salmonella, and Vibrio, and could be therefore applicable for use as a bacteriostatic agent.