Antibacterial effect of citral on yersinia enterocolitica and its mechanism

Yersinia enterocolitica is a pervasive pathogen associated with foodborne infections. Citral is an FDA-certified food safety ingredient derived from plants because citral has antioxidant, antibacterial and anticancer properties. This study was conducted to investigate the antibacterial activity of citral against Y. enterocolitica and its possible antimicrobial mechanism. The minimum inhibitory concentrations (MIC) and minimal bactericidal concentration (MBC) of citral against Y. enterocolitica ATCC 23715 were 0.2 and 0.4 mg/mL, respectively, and Y. enterocolitica treated with citral showed an obvious reduction in growth rate compared with an untreated control. Citral was also found to increase the level of reactive oxygen species in cells, induce morphological changes in cells, and cause cell membrane dysfunction, as evidenced by cell membrane hyperpolarization, decreased cell membrane integrity and intracellular ATP concentration. Sodium dodecyl sulfate-poly-acrylamide gel electrophoresis (SDS-PAGE) analysis confirmed the effects of citral on proteins synthesis by Y. enterocolitica, while reverse transcription-quantitative real-time PCR (RT-qPCR) indicated that the transcription of multiple genes associated with virulence of Y. enterocolitica, such as ail, myfA, ystA, pspB, phoQ and gsrA, was reduced by citral. Moreover, citral effectively inactivated Y. enterocolitica in PBS, LB broth, and fresh vegetable juice. These findings suggest that citral has the potential for use as a natural antimicrobial agent to control Y. enterocolitica in vegetables and other areas of the food supply chain, thereby reducing the risk of Y. enterocolitica infection.