The Antimicrobial Activity of Mentha longifolia L. Essential Oil and Lactobacillus casei on Growth of Listeria monocytogenes During the Manufacture, Ripening, and Storage of Iranian white Cheese

Background: Food preservation includes procedures to assure higher level of food safety, hygiene and stability. To achieve this goal, the use of combination biopreservatives, such as Essential oils and Probiotics, has gained increased attention. Objective: The aim of this study was to evaluate the antimicrobial effects of Mentha longifolia L. esential oil and Lactobacillus casei aginst Listeria monocytogenes in Iranian white cheese. Methods: The essential oil of this plant was prepared by steam distillation and analyzed by GC/MS method. The inhibitory effect of different concentrations of this essential oil and Lactobacillus casei against Listeria monocytogenes were determined by the method of viable colony count on the selective media in different interval of production and storage of Iranian white cheese. Results: The results showed that 0.03 and 0.015 % of this essential oil when used in combination with Lactobacillus casei had the highest inhibitory effect on the growth of Listeria monocytogenes, Furthermore, 0.015% of this essential oil combined with Lactobacillus casei had not only inhibitory effect on growth of Listeria monocytogenes but also maintained optimum taste quality of the cheese. Conclusion: The effects of used concentrations of Mentha longifolia L. essential oil and Lactobacillus casei showed significantly higher antibacterial activity compared to the control and treatments containing essential oil without probiotic bacteria. This reveals inhibitory effect of essential oil of Mentha longifolia L. and Lactobacillus casei against Listeria monocytogenes. It was concluded that lower concentrations of Mentha longifolia L. essential oil could be used for inhibitory activity combined with probiotic bacteria.