Quantitative polymerase chain reaction-based method for the rapid detection and quantification of Listeria monocytogenes from food products.

Listeria monocytogenes (LM) is found in various environmental sources, including animal intestinal tracts, soil, and sewage. LM can contaminate various food products, including meat, seafood, cheese, fruits, and vegetables. Individuals with underlying medical conditions, the elderly, pregnant women, and infants, may develop meningitis and sepsis upon consuming LM-contaminated food. A rapid and standardized quantification method for evaluating initial contamination levels of LM in food remains to be established. This study aimed to develop a rapid quantification method to monitor LM contamination in food handling facilities. A regression equation was developed to determine the concentrations of LM cells before and after enrichment. Regression equations developed to estimate LM cell concentrations in food samples (ground poultry and green salad) were evaluated. The concentrations of LM cells in ground poultry and green salad before enrichment were 2.44 and 2.92 log10 CFU/g, respectively, and the concentrations obtained using a rapid qPCR-based detection and quantification method were 2.05 and 3.27 log10 CFU/g, respectively. The proposed method can semi-quantitatively estimate LM contamination at approximately 102 CFU/g of food, which is the maximum allowable level of LM contamination in foods. This study may serve as a basis for establishing and improving hygiene management systems and preventing listeriosis.