Loop-Mediated Isothermal Amplification for Detecting Four Major Foodborne Pathogens in Meat and Meat Products

<i>Listeria monocytogenes</i>, <i>Staphylococcus aureus</i>, <i>Salmonella enterica</i>, and <i>Escherichia coli</i> O157:H7 are four major foodborne pathogenic bacteria found in meat and meat products, which pose significant threats to human health. In this study, we developed specific loop-mediated isothermal amplification (LAMP) primers targeting these four pathogenic bacteria. Following the optimization of system components and reaction parameters, four rapid and simplified LAMP-based detection assays were established, which enabled the visual detection of these four pathogenic bacteria within 40-50 min. The three established LAMP assays targeting <i>L. monocytogenes</i>, <i>S. aureus</i>, and <i>E. coli</i> O157:H7 achieved species-level discrimination, whereas the LAMP method for <i>Salmonella</i> exhibited genus-level specificity. The detection limits of the LAMP assays were determined as follows: 1.8 × 10¹ colony forming units (CFU)/mL for <i>L. monocytogenes</i>, 5.1 × 10¹ CFU/mL for <i>S. aureus</i>, 1.2 × 10¹ CFU/mL for <i>S. enterica</i>, and 3.3 × 10³ CFU/mL for <i>E. coli</i> O157:H7, with sensitivity improved by 10-1000-fold compared to conventional PCR. The developed LAMP assays were used to analyze 52 meat and meat product samples, and 7 samples were positive, which was consistent with the results of the conventional PCR and culture-based methods, demonstrating an accuracy rate of 100% for the LAMP methods. In conclusion, the established LAMP assays exhibit high specificity, enhanced sensitivity, and result visualization, making them suitable for on-site rapid detection in food safety monitoring.