Application of a Loop-Mediated Isothermal Amplification (LAMP) Assay for the Detection of Listeria monocytogenes in Cooked Ham

Changing eating habits and rising demand of food have increased the incidence of foodborne diseases, particularly in industrialized countries. In this context, contaminated ready-to-eat food (RTE) may be a vehicle for the transmission of Listeria monocytogenes (L. monocytogenes), a foodborne pathogen responsible of listeriosis, a severe infectious disease involving humans and animals. It would be useful to have rapid detection methods to screen the presence of L. monocytogenes in food. In this study, a colorimetric Loop-mediated isothermal amplification (LAMP) assay was applied to the detection of L. monocytogenes in 37 experimentally contaminated RTE meat samples. The LAMP primers consisted of a set of six primers targeting eight regions on the hlyA gene; the assay was carried out in 30 min at 65 degrees C in a water bath. Amplification products were visualized by color change assessment. The results of colorimetric LAMP assays based on the hly gene obtained in this study were compared to microbiological cultural methods, real-time PCR and real-time LAMP PCR, which show 100% specificity and sensitivity. These data suggest that colorimetric LAMP assays can be used as a screen to detect L. monocytogenes in ready-to-eat meat food.

Automated summary

Changing eating habits and rising demand of food have led to an increase in foodborne diseases, particularly in industrialized countries. Contaminated ready-to-eat food can transmit Listeria monocytogenes, a foodborne pathogen responsible for listeriosis. This study successfully applied a colorimetric Loop-mediated isothermal amplification (LAMP) assay to rapidly detect L. monocytogenes in experimentally contaminated RTE meat samples. The results showed high specificity and sensitivity compared to traditional methods, suggesting that colorimetric LAMP assays can be used as a screening tool for L. monocytogenes in ready-to-eat meat food.