Rapid and visual detection of Listeria monocytogenes based on polymerase spiral reaction in fresh-cut fruit

Abstract

Widespread foodborne pathogen Listeria monocytogenes exhibits a pronounced fatality rate among individuals with compromised immune systems, the elderly, and pregnant women. A simple and user-friendly approach is required to identify L. monocytogenes. A distinctive thermostatic nucleic acid amplification technology called polymerase spiral reaction (PSR) has been extensively employed in the identification of foodborne pathogens. In the study, a straightforward and intuitive approach for identifying L. monocytogenes in fresh-cut fruit was established using PSR in conjunction with hydroxy naphthol blue (HNB). Following optimization, the system's primary constitutes-betaine, dNTP, and MgSO4 were found to be 0.5 M, 1.0 mM, and 6 mM, respectively. Six strains of non- L. monocytogenes were used to test the assay's specificity. The PSR assay performed at 65 °C for 50 min demonstrated the capability to detect L. monocytogenes at level as low as 1 × 10−4 ng/μL DNA per tube and 5.1 × 101 CFU/g of freshly cut fruit. Notably, the sensitivity of this approach surpassed that of PCR by10-fold (1 × 10−3 ng/μL). In order to detect L. monocytogenes, the PSR assay was designed to be rapid, accurate, effective, and apparatus free. This innovative assay has provided researchers a fresh perspective on identification harmful microorganisms.