The effect of Mentha piperita L. essential oil in comparison with its alco-holic extracts against some food problematic microorganisms

One of the main challenges for food producers is to ensure the health and high quality of food during the production, storage and consumption stages. Due to the concern about the safety of chemical antimicrobial compounds, the use of medicinal plants and their health properties in the food industry can ensure the health of consumers. So, the objective of this study was to evaluate antimicrobial activity of essential oil, ethanolic and methanolic extracts of Mentha piperita L cultivated in Medicinal plants farm of agricultural research institute of zabol university, against spoilage and pathogenic microorganisms in food products including Pseudomonas aeruginosa, Bacillus cereus, Micrococcus luteus, listeria monocytogenes and Escherichia coli. The essential oil was obtained by water-distillation using a Clevenger-type system and ethanolic and methanolic extracts were obtained by wet method. Antimicrobial activity of the extracts was measured by agar well diffusion method and minimum inhibitory concentration (MIC) was subsequently determined. The results of diameter of inhibition zone and MIC values indicate that antibacterial activity of the extracts of Mentha piperita L was related to the type of extract and the type of microorganism. Unlike methanolic and ethanolic extracts of Mentha piperita L, which were ineffective in all concentrations against Listeria monocytogenes (0 mm), its essential oil had a strong inhibitory effect on all studied bacteria and with diameter of inhibition zone of 39.3 mm showed the highest significant antimicrobial activity on the same microorganism. In this study, Pseudomonas aeruginosa was the most resistant bacteria to the essential oil and methanolic extracts. The findings of this study indicated that Mentha piperita L essential oil has a strong antimicrobial activity on spoilage and pathogenic microorganisms associated with food.  Therefore, the mentioned compound can be suggested as a very valuable antimicrobial preservative in food.