Effects of cinnamon essential oil on the physiological metabolism of Salmonella enteritidis.

Food safety and health are the themes of today's society. As a class of foodborne pathogens, Salmonella enteritidis has become one of the common zoonotic pathogens. Because chemical preservatives have certain harmfulness and have been questioned, it is particularly important to find green and safe natural preservatives. The advantages of plant essential oils (EOs) are that they are green and safe, have a wide range of antibacterials, and are not easy to form drug resistance. In recent years, studies have found that EOs have excellent antibacterial activity, but their antibacterial mechanism has not been conclusive, which has certain limitations in their application in the food field. Cinnamon essential oil (CEO) extracted from dried cinnamon is a secondary metabolite of cells and a very important natural food flavor. More importantly, it is non-toxic to the human body and has been proven to have a good antibacterial effect, but its antibacterial mechanism is still unclear. Therefore, it was of great practical significance to carry out the research on the antibacterial mechanism of CEO on S. enteritidis. In this work, S. enteritidis was used as the test bacteria, and CEO was selected as the antibacterial agent to study the antibacterial mechanisms. By studying the physiological metabolism of S. enteritidis cells by CEO, the influence of CEO on the bacteriostatic mechanism of S. enteritidis was systematically elucidated. The study found that CEO treatment would reduce the activity of bacterial metabolism. It is mainly reflected in the following three aspects: first, the activity of key enzymes in TCA circulation is inhibited, thus affecting the respiration of S. enteritidis. Second, it affects the level of energy metabolism by inhibiting the content of adenosine triphosphate (ATP) and the activity of ATPase. Finally, it can affect the physiological metabolism of bacteria by inhibiting the metabolism of proteins and other substances. Therefore, this article was expected to provide a theoretical basis for the development of new natural food preservatives and the prevention and control of S. enteritidis.

Zhang Z ，Zhao Y ，Chen X ，Li W ，Wang L ，Li W ，Du J ，Zhang S ... -  《Frontiers in Microbiology》

Effects of Cinnamon Essential Oil on Oxidative Damage and Outer Membrane Protein Genes of Salmonella enteritidis Cells.

Zhang Z ，Zhao Y ，Chen X ，Li W ，Li W ，Du J ，Wang L ... -  《Foods》

Controlled-release casein/cinnamon essential oil nanospheres for the inactivation of Campylobacter jejuni in duck.

Campylobacter jejuni (C. jejuni) is one of the most common foodborne pathogens that cause human sickness mostly through the poultry food chain. Cinnamon essential oil (CEO) has excellent antibacterial ability against C. jejuni growth. This study investigated the antibacterial mechanism of CEO against C. jejuni primarily through metabolism, energy metabolism of essential enzymes (AKPase, β-galactosidase, and ATPase), and respiration metabolism. Results showed that the hexose monophosphate pathway (HMP) was inhibited, and that the enzyme activity of G6DPH substantially decreased upon treatment with CEO. Analysis of the effect of CEO on the expression of toxic genes was performed by the real-time PCR (RT-PCR). The expression levels of the toxic genes cadF, ciaB, fliA, and racR under CEO treatment were determined. Casein/CEO nanospheres were further prepared for the effective inhibition of C. jejuni and characterized by particle-size distribution, zeta-potential distribution, fluorescence, TEM, and GC-MS methods. Finally, the efficiency of CEO and casein/CEO nanospheres in terms of antibacterial activity against C. jejuni was verified. The casein/CEO nanospheres displayed high antibacterial activity on duck samples. The population of the test group decreased from 4.30 logCFU/g to 0.86 logCFU/g and 4.30 logCFU/g to 2.46 logCFU/g at 4 °C and at 25 °C for C. jejuni, respectively. Sensory evaluation and texture analysis were also conducted on various duck samples.

Cui H ，Yang H ，Abdel-Samie MA ，Siva S ，Lin L ... -  《-》

Antibacterial Effects of Ultrasound, Cinnamon Essential Oil, and Their Combination Against Listeria monocytogenes and Salmonella Typhimurium in Milk.

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 low- and 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.

Mortazavi N ，Aliakbarlu J 《-》

Essential Oils of Mentha arvensis and Cinnamomum cassia Exhibit Distinct Antibacterial Activity at Different Temperatures In Vitro and on Chicken Skin.

Vepštaitė-Monstavičė I ，Ravoitytė B ，Būdienė J ，Valys A ，Lukša J ，Servienė E ... -  《-》