Listeria monocytogenes-Can We Reduce or Eliminate It From Food Commodities?

Abstract

Listeria monocytogenes is a highly virulent foodborne pathogen responsible for listeriosis, a severe infection threatening vulnerable populations such as pregnant women, newborns, the elderly, and immunocompromised individuals. Its resilience, surviving low pH, reduced water activity, and refrigeration, makes it a formidable contaminant in food systems. Traditional control methods include heat treatment, high-pressure processing, irradiation, and acidification, all aimed at reducing bacterial load in ready-to-eat foods. WHO and FAO guidelines emphasize minimizing contamination and growth. Emerging strategies target gene expression to curb virulence and survival. External signals like chitin can suppress pathogenic genes, while nucleomodulins alter host chromatin to disrupt infection. Regulatory proteins such as MogR and GmaR modulate motility-related genes, and selective pressures from antimicrobials or bacteriophages can reshape bacterial behavior. Genetic tools like CRISPR-Cas9 offer precision editing of key genes. Additional interventions include environmental adjustments (temperature, pH, salinity), bacteriophage applications (e.g., PhageGuard Listex, ListShield), and competitive exclusion via beneficial microbes. Natural antimicrobials like bacteriocins (nisin, pediocin, enterocin, plantaricins, and lactocin S) disrupt cell walls and membranes. Phenolic compounds such as allicin, eugenol, and curcumin also exhibit inhibitory effects. Combining these approaches is vital for effective control and enhanced food safety.