Abstract:This study investigated the inhibitory effect of tea tree essential oil on Listeria monocytogenes and its application in the preservation of chilled fresh pork. The minimum inhibitory concentration (MIC) of tea tree essential oil against Listeria monocytogenes was determined, and the bacterial growth curve and the changes in cell microstructure were observed. The changes in the total bacterial count, total volatile basic nitrogen content, thiobarbituric acid reactive substances content, pH, color, and texture of the pork treated with the tea tree essential oil during refrigeration were analyzed. The results showed that the MIC of tea tree essential oil against Listeria monocytogenes was 4.0 mg/mL, and different treatments with tea tree essential oil exhibited a significant inhibitory effect on Listeria monocytogenes. The tea tree essential oil damaged the structural integrity of the cell membranes and cell walls of Listeria monocytogenes, causing the release of internal cellular contents and ultimately the death of bacteria. Compared with the control group, the total colony number of MIC, 2MIC and 4MIC of the tea tree essential oil treatment groups decreased by 1.18, 1.37 and 1.56 log CFU/g, respectively, and the values of TVB-N and TBARS did not exceed the maximum threshold during storage (0~12 days). Therefore, tea tree essential oil effectively inhibited the growth of microorganisms in pork, delayed the degradation of nitrogen-containing compounds, fat oxidation, color and quality changes in the pork. The results showed that tea tree essential oil could inhibit the growth of Listeria monocytogenes and extend the shelf life of chilled fresh pork for about 3 days, and can be used as a preservative for chilled pork.
