Application of Artemisia absinthium essential oil to the control of pathogenic bacteria growth on fresh lettuce

Today, because of the side effects of chemical preservatives, it is suggested to use natural antimicrobial compounds such as essential oils. The antimicrobial activities of essential oils are well recognized for many years. In this study, after preparation of Artemisia absinthium essential oil, its components were identified by Gas chromatography–mass spectrometry (GC-MS). Then antibacterial activity of the essential oil was evaluated against Staphylococcus aureus, Escherichia coli, Salmonella typhi and Bacillus cereus by agar disk-diffusion, MIC and MBC methods. Based on MIC results, essential oil concentrations of 16, 32 and 64 (µl/ml) were selected to evaluate its efficacy in inactivating the growth of pathogenic bacteria on fresh lettuce. Lettuce was inoculated with Staphylococcus aureus, Escherichia coli, Salmonella typhi and Bacillus cereus and the bacterial count were enumerated at time intervals (0 h, 3 h, 24 h, and 72 h). The concentration of (Z)-β-Ocimene oxide as the major component of the essential oil was 76.53±2.36%. The results of MIC, MBC values and agar disk-diffusion showed that the most sensitive and the most resistant bacteria were Staphylococcus aureus and Escherichia, respectively. Compared to control (water), lettuce treated with 64 µl/ml essential oil at 72 h after treatment showed an up to 3.36, 2.27, 3.23 and 3.47 log CFU/g reductions in Staphylococcus aureus, Escherichia coli, Salmonella typhi and Bacillus cereus, respectively. This research showed that Artemisia absinthium essential oil may be an effective antimicrobial agent to the Control of pathogenic bacteria growth on fresh lettuce.