Inhibitory effects of Ajowan essential oil on growth of Listeria monocytogenes in Rutilus frissi kutum broth medium and fillet

Due to consumers'' concerns regarding the adverse side effects of chemical preservatives and increased bacterial strains'' resistance to commonly used antibacterial agents، research to find natural compounds to replace these agents seems warranted. The main aim of this study was to assess the inhibitory effects of Ajowan essential oil on growthb of Listeria monocytogenes in both kutum broth and kutum flesh models. In the first step، the highest concentration of Ajowan essential oil with no significant changes on sensory properties of kutum was detemined. Then effects of the oil at concentrations of 0. 05، 0. 15 and 0. 3% and salt at concentations of 0% and 4% on growth of Listeria monocytogenes inoculated in a kutum broth were assessed، followed by assessing the effects of the oil at a concentration of 0. 15% and 0. 3% on growth of Listeria monocytogenes in the kutum flesh model. The samples were stored at 4° C for 12 days، bacterial counting being performed at 4-day intervals. In the kutum broth، Ajowan oil at a concentration of 0. 15% demonstrated a bacteriostatic effect; a concentration of 0. 3% was needed to be effective against Listeria monocytogenes. Addition of 4% salt to fish broth significantly improved the antibacterial activity of the oil. Further analysis of the data showed that in kutum flesh a concentration of 0. 15 and 0. 3% Ajowan oil significantly reduced bacterial growth as compaed with the control value. The use of Ajowan oil can significantly prevent the growth of Listeria monocytogenes. The effect is more pronounced in the fish broth medium than in the kutum fillets.