FOOD SCIENCE ›› 2019, Vol. 40 ›› Issue (13): 22-27.doi: 10.7506/spkx1002-6630-20180630-540

• Basic Research • Previous Articles     Next Articles

Antimicrobial Activity and Mechanism of Carvacrol against Enterobacter cloacae

ZHOU Qi, YUAN Kang, LIU Fang, DU Lihui   

  1. 1. Collaborative Innovation Center for Modern Grain Circulation and Safety, Key Laboratory of Grains and Oils Quality Control and Processing, College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; 2. Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
  • Online:2019-07-15 Published:2019-07-23

Abstract: Carvacrol has a good bacteriostatic effect and can meet people’s requirements for safe food preservatives without any toxic or side effects. In the present study, the minimum inhibitory concentration (MIC) and bactericidal activity of carvacrol against Gram-negative Enterobacter cloacae (C4) were detected, and the cell membrane potential and extracellular ATP content of E. cloacae treated by carvacrol were measured. A laser scanning confocal microscope was used to detect the cell permeability, and a scanning electron microscope was used to observe the cell morphology. Furthermore, the antibacterial mechanism was discussed. The results showed that the MIC of carvacrol against E. cloacae was 0.5 μL/mL. The permeability of the cytoplasmic membrane was increased when the carvacrol concentration was raised from 0.25 to 2 μL/mL. The membrane potential changed and ATP leaked out from the cells after this treatment. Scanning electron microscope (SEM) images revealed the treated bacterial cells became dry and cracked. Carvacrol concentrations above 1 μL/mL almost solubilized the bacterial cells. Thus, carvacrol may exert its inhibitory effect on E. cloacae mainly by simultaneously changing the cell membrane permeability and the cell membrane potential, thereby resulting in massive leakage of intracellular components, such as ATP.

Key words: carvacrol, Enterobacter cloacae, antibacterial mechanism

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