This study examined the antibacterial mode of action of Taxus cuspidata leaf essential oil (TCEO) against foodborne pathogenic bacteria. Gas chromatography–mass spectrometry analysis of microwave-extracted TCEO resulted in examination of 34 different compounds, representing 81.63% of the total oil. The TCEO (1,000 μg per disc) showed antibacterial effect against Bacillus cereus ATCC 13061, Staphylococcus aureus ATCC 12600, Listeria monocytogenes ATCC 7644, Salmonella typhimurium ATCC 43174 and Escherichia coli ATCC 43889 as diameters of inhibition zones (22.0 ± 0.4 to 34.0 ± 1.2 mm). The minimum inhibitory concentration and minimum bactericidal concentration values of TCEO against the tested pathogens were found in the range of 250–1,000 μg/mL. Also, the TCEO had potential inhibitory effect on the viable counts of test pathogens. The TCEO revealed its mode of action on membrane integrity as confirmed by marked release of extracellular adenosine triphosphate, 260 nm absorbing materials and potassium ion efflux. The scanning electron microscopy analysis using TCEO further confirmed severe morphological alterations on the cell membrane of test pathogens.
Because of frequent foodborne outbreaks and rising concern of consumers on the use of chemical preservatives in foods, the food industry is emphasizing the use of natural antibacterial agents from plant origin as safe food preservatives. Some selected plant materials are used as natural antimicrobials in food systems to prevent the growth of foodborne pathogens, resulting in the extension of shelf life of processed foods. Taxus cuspidata leaf essential oil (TCEO) is shown by this study to elicit its antibacterial action against foodborne pathogens through membrane permeabilization and can be used to control the growth of several foodborne pathogens. Hence, it is anticipated that TCEO may have greater potential for its practical application as an affective food preservative.