The combination of thymol and cinnamaldehyde reduces the survival and virulence of Listeria monocytogenes on autoclaved chicken breast.

ABSTRACT

AIMS: To reveal the antibacterial mechanism of the combination of thymol and cinnamaldehyde to Listeria monocytogenes ATCC 19115 on autoclaved chicken breast. METHODS AND RESULTS: In this study, L. monocytogenes ATCC 19115 on autoclaved chicken breast was exposed to the stress of 125 µg/ml thymol and 125 µg/ml cinnamaldehyde, and transcriptome analysis was used to reveal the crucial antibacterial mechanism. According to the results, 1303 significantly differentially expressed genes (DEGs) were identified. Treated by thymol and cinnamaldehyde in combination, pyrimidine and branched-chain amino acid biosynthesis of L. monocytogenes were thwarted which impairs its nucleic acid biosynthesis and intracellular metabolism. The up-regulated DEGs involved in membrane composition and function contributed to membrane repair. Besides, pyruvate catabolism and TCA cycle were restrained which brought about the disturbance of amino acid metabolism. ABC transporters were also perturbed, for instance, the uptake of cysteine, D-methionine, and betaine was activated, while the uptake of vitamin, iron, and carnitine was repressed. Thus, L. monocytogenes tended to activate PTS, glycolysis, glycerol catabolism, and pentose phosphate pathways to obtain energy to adapt to the hostile condition. Noticeably, DEGs involved in virulence factors were totally down-regulated, including genes devoted to encoding flagella, chemotaxis, biofilm formation, internalin as well as virulence gene clusters. CONCLUSIONS: The combination of thymol and cinnamaldehyde is effective to reduce the survival and potential virulence of L. monocytogenes on autoclaved chicken breast. SIGNIFICANCE AND IMPACT OF STUDY This work contributes to providing theoretical information for the application and optimization of thymol and cinnamaldehyde in ready-to-eat meat products to inhibit L. monocytogenes.