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Eugenol (2-Methoxy-4-(2-Propenyl) Phenol; EUG) is a natural antibacterial ingredient of the essential oil from many aromatic plants. The antimicrobial mechanism of EUG and its combined inactivation effect with pulsed electric fields (PEF) treatment in a hurdle strategy on E. coli ATCC 8739 were investigated. Results showed that membrane integrity and the morphology of E. coli cell were damaged and the membrane permeability was increased when E. coli was exposed to higher levels of EUG. Analysis of fluorescence spectra, molecular docking and atomic force microscope indicated that EUG bound to the AT-rich region of DNA through groove binding mode, leading to morphological alterations and the aggregation of DNA molecules. The combinations of EUG and PEF demonstrated strong synergistic effects for sterilization and it was proven to be an effective method to achieve a higher level of E. coli inactivation. • Eugenol induced an increase in membrane permeability of E. coli cells. • Eugenol destroyed membrane integrity and morphology of E. coli cell. • Eugenol bound to the AT-rich region of DNA of E. coli through groove binding mode. • The binding resulted in morphological alterations and aggregation of DNA molecules. • Combination of eugenol and PEF showed a strong synergistic effect against E. coli. [ABSTRACT FROM AUTHOR]

Eugenol (EUG; 4‐allyl‐2‐methoxyphenol) is a natural antibacterial component from essential oil. The effects of EUG on cell membrane fatty acid composition, membrane fluidity and resistance to pulsed electric field (PEF) of Escherichia coli ATCC 8,739 (E. coli) were investigated. Results indicated that the PEF resistance of E. coli decreased as EUG concentration increased, which may be related to the alterations in membrane fatty acid composition and fluidity. Gas chromatography−mass spectrometry and micro‐Raman spectroscopy showed that EUG increased membrane fluidity by notably increasing the proportion of unsaturation fatty acids and simultaneously decreasing the content of cyclic fatty acids. These results revealed that PEF resistance of E. coli was influenced by EUG due to alterations of fatty acid composition and membrane fluidity. Practical applications: Pulsed electric field (PEF), as a widely used non‐thermal sterilization technology, has gained much attention and increasingly focused on improving the efficiency to inactivate micro‐organisms. Eugenol (EUG; 4‐allyl‐2‐methoxyphenol) derived from cloves is a natural phenol essential oil and exhibits several pharmacological properties such as being an antimicrobial. Our results revealed the underlying mechanism that EUG reduced PEF resistance of E. coli cells and contributed to achieve better understanding of microbial inactivation by PEF. Therefore, a new route for the application of eugenol to improve the efficiency of PEF in the food industry was created. [ABSTRACT FROM AUTHOR]