Adaptive Responses of Listeria monocytogenes to Nutrient Stress and Detergent Resistance

The ability of Listeria monocytogenes to survive under nutrient-deprived conditions may significantly impact L. monocytogenes viability in food and food safety. This study aimed to investigate the viability of L. monocytogenes against detergents in different nutrient states and the relevant survival mechanism. Key observations revealed an increased tolerance of L. monocytogenes to Sodium Dodecyl Sulfate (SDS) following nutrient stress, notably in the 1/100 TSB-YE (Tryptic Soy Broth-Yeast Extract) group. The injury rate of the 1/100 TSB-YE group was significantly lower than that of other nutrient groups (P < 0.05). Besides, morphological adaptations to nutrient stress were characterized by increased cell length and volume, accompanied by an upsurge in the secretion of extracellular substances. Transcriptome analysis revealed significant gene expression changes in response to nutrient dilution and starvation, with a notable number of differentially expressed genes (DEGs) involved in membrane components, ATP binding, and metabolic processes, which were validated through the RT-qPCR tests. This study demonstrates that nutrient stress can impede the growth of L. monocytogenes, but also induces a cross-protection response against SDS. These findings could be supplemented with its inactivation parameters to the risk assessment system and the response to stress was provided a theoretical reference for the prevention and control of L. monocytogenes.