title: Antimicrobial Activity and Possible Mechanism of Action of Citral against Cronobacter sakazakii.
abstract: Citral is a flavor component that is commonly used in food, beverage and fragrance industries. Cronobacter sakazakii is a food-borne pathogen associated with severe illness and high mortality in neonates and infants. The objective of the present study was to evaluate antimicrobial effect of citral against C. sakazakii strains. The minimum inhibitory concentration (MIC) of citral against C. sakazakii was determined via agar dilution method, then Gompertz models were used to quantitate the effect of citral on microbial growth kinetics. Changes in intracellular pH (pHin), membrane potential, intracellular ATP concentration, and membrane integrity were measured to elucidate the possible antimicrobial mechanism. Cell morphology changes were also examined using a field emission scanning electron microscope. The MICs of citral against C. sakazakii strains ranged from 0.27 to 0.54 mg/mL, and citral resulted in a longer lag phase and lower growth rate of C. sakazakii compared to the control. Citral affected the cell membrane of C. sakazakii, as evidenced by decreased intracellular ATP concentration, reduced pHin, and cell membrane hyperpolarization. Scanning electron microscopy analysis further confirmed that C. sakazakii cell membranes were damaged by citral. These findings suggest that citral exhibits antimicrobial effect against C. sakazakii strains and could be potentially used to control C. sakazakii in foods. However, how it works in food systems where many other components may interfere with its efficacy should be tested in future research before its real application.
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Shi
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Kaikuo
authors.initials: K
authors.lastname: Song
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Sun
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Sui
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Chen
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Jia
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Huihui
authors.initials: H
authors.lastname: Sun
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Sun
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.|Sino-US Joint Research Center for Food Safety, Yangling, Shaanxi, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xia
mesh_terms: D000080462:Acyclic Monoterpenes; D000255:Adenosine Triphosphate / Q000032:analysis; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D044083:Cronobacter sakazakii / Q000737:chemistry / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D039821:Monoterpenes / Q000494:pharmacology*
chemical_list: D000080462:Acyclic Monoterpenes; D000900:Anti-Bacterial Agents; D039821:Monoterpenes; D000255:Adenosine Triphosphate; C007076:citral