The antibacterial effects of ultrasound (US) and cinnamon essential oil (CEO), individually and combined, were investigated against Listeria monocytogenes and Salmonella Typhimurium in low-and high-fat milk during 6-day storage. At the end of storage, CEO alone decreased 2 and 2.2 log cycles of Salmonella Typhimurium and 2.5 and 3 log cycles of L. monocytogenes populations in low-and high-fat milk, respectively. US alone reduced 1.6 log cycle of Salmonella Typhimurium and 0.7 log cycle of L. monocytogenes in both milk type. The combined treatment could reduce 2.7 log cycle of Salmonella Typhimurium in low-fat milk and 3.8 log cycle in high-fat milk. The combined treatment also achieved 4.3 and 4.5 log cycle reductions of L. monocytogenes in low-and high-fat milk, respectively. The results of this study showed that the combination of CEO and US could be used as an effective antibacterial treatment in milk.Practical Applications: Due to adverse effects of thermal processing on the sensory and nutritional properties of food and the potentially harmful effects of chemical preservatives, nonthermal preservation methods and natural antimicrobials have been gained much attention. In this study, the antibacterial effects of ultrasound (US) and cinnamon essential oil (CEO), individually and combined, were investigated against Listeria monocytogenes and Salmonella Typhimurium in lowand high-fat milk. The results indicated that combination of US and CEO could significantly decrease L. monocytogenes and Salmonella Typhimurium populations in milk. Then, this combined treatment may be used as an effective alternative method to microbial inactivation in milk.

The aim of this study was to investigate the antibacterial interactions of pulegone and 1,8‐cineole with monolaurin ornisin against Staphylococcus aureus . The individual and combined antibacterial activities of the compounds were evaluated using minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), fractional inhibitory concentration index (FICi), and time‐kill methods. Furthermore, the mechanism of the antibacterial action of the compounds was tested by measuring the release of cell constituents. The MIC values of pulegone, 1,8‐cineole, nisin, and monolaurin were 5.85 µl/ml, 23.43 µl/ml, 6.25 µg/ml, and 0.031 mg/ml, respectively. A synergistic antibacterial activity (FICi = 0.5) was found between 1,8‐cineole and nisin. The time‐kill assay showed that the populations of S. aureus exposed to 1,8‐cineole, nisin, and their combination were decreased by 5.9, 5.3, and 7.1 log CFU (colony‐forming units)/mL, respectively. The combination of 1,8‐cineole and nisin also induced the highest release of cell constituents. It was concluded that the combination of 1,8‐cineole and nisin could be considered as a novel and promising combination which may reduce the required dose of each antibacterial compound.

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