Adaptive Tolerance of Listeria monocytogenes to Chemical Oxidants: Comparative Analysis of Transcriptomic Studies

Listeria monocytogenes is a foodborne pathogen that poses significant challenges to food safety and public health due to its ability to adapt to harsh environments, particularly those found in food processing facilities. This review explores the global transcriptional responses of L. monocytogenes to various chemical oxidants, including hydrogen peroxide, chlorine dioxide, ozone, and plasma-activated water. By comparing the transcriptomic data of multiple studies, we identified the differentially expressed genes associated with key cellular processes, including oxidative stress responses, cell envelope biosynthesis, metabolic adaptation, efflux mechanisms, and virulence regulation. This review demonstrates that L. monocytogenes employs distinct gene expression patterns to resist disinfectant stress, primarily by upregulating efflux pumps, reactive oxygen species detoxification mechanisms, and DNA repair pathways as well as modulating central metabolism. Several disinfection treatments commonly affect the key genes related to peptidoglycan biosynthesis, cell envelope, cell division, glycolysis, oxidative stress response, and chemotaxis. Although oxidizing agents induce widely conserved gene expression patterns, other treatments trigger unique responses. However, interpretation of different study findings is restricted by methodological inconsistencies, including variations in treatment conditions, media, bacterial states, and transcriptomic techniques. These variations and nonuniform fold change thresholds for differentially expressed genes complicate the comparison of different studies. Therefore, standardized frameworks are necessary to elucidate the adaptive responses of L. monocytogenes and refine its disinfection methods in food processing.