Evaluation and Optimization of a Loop-Mediated Isothermal Amplification (LAMP) Assay for the Detection of Salmonella enterica serovar Typhi Isolated from Food Samples

Foodborne diseases caused by Salmonella are considered as a global health concern, especially in low-income countries. Rapid and specific detection of this infective agent is highly important in the outbreak control. The current study aimed to design and optimize a LAMP method and to compare its sensitivity and efficiency with the PCR method in the detection of S. typhi in food.

Food samples including mayonnaise and vegetable salad were inoculated with S. enterica serovar Typhi. Sensitivity and detection limit of LAMP test were investigated at different concentrations of contaminated mayonnaise and vegetable salad. invA gene was chosen as the target gene for bacterial detection by PCR and LAMP tests.

The detection limit of Samonella was estimated to be 16 CFU/mL using LAMP and PCR. LAMP reaction revealed a visible turbidity, indicating the accurate amplification of the selected target gene and proper identification of Salmonella at different dilutions of the studied food samples.

The present study indicated that LAMP is a rapid, cost-effective, and specific technique for the identification of Salmonella. This method could be used in laboratories with minimal equipment without the need for costly molecular detection methods.