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Surface Monitoring of L. Monocytogenes by Real-time Fluorescence and Colorimetric LAMP

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Abstract

Listeria monocytogenes is a major foodborne pathogen affecting developing, and developed countries. The analysis of food contact surfaces in food industries is key for better controlling this pathogen. The current study focused on the development, optimization, and evaluation of a rapid and simple method for the detection of L. monocytogenes on stainless steel surfaces, suitable for decentralized setups, taking advantage of Loop-mediated isothermal amplification (LAMP). This was accomplished using a general pre-enrichment broth (TSB), with a simple DNA extraction based on a chelating resin, and final isothermal amplification. Two different detection strategies were tested, real-time fluorescence and naked-eye colorimetric, which were evaluated after 5, 7, and 24 h of pre-enrichment. Regardless the detection chemistry selected, after 5-7 h of pre-enrichment, 10-10 CFU/cm were needed to obtain a positive result, while after 24 h, it was possible to detect concentrations below 10 CFU/cm. Within each given time, all the performance parameters calculated, relative sensitivity, specificity, and accuracy, reached values higher than 80-90%; likewise, a Cohen's k of concordance with a culture-based approach higher than 0.8. Overall, the most sensitive assay can be performed in roughly 25 h. This time-to-result outperforms commercial kits with the added value of specifically detecting L. monocytogenes instead of Listeria spp. KEY POINTS: • Real-time fluorescence and naked-eye colorimetric, were compared for the novel assay. • An LOD50 of 3.4 CFU/cm and 4.2 CFU/cm was calculated for the two assays. • Three pre-enrichment times were compared providing 24 h better results.

References
1.
Garrido-Maestu A, Prado M . Naked-eye detection strategies coupled with isothermal nucleic acid amplification techniques for the detection of human pathogens. Compr Rev Food Sci Food Saf. 2022; 21(2):1913-1939. DOI: 10.1111/1541-4337.12902. View

2.
Rodriguez-Lazaro D, Jofre A, Aymerich T, Garriga M, Pla M . Rapid quantitative detection of, Listeria monocytogenes in salmon products: evaluation of pre-real-time PCR strategies. J Food Prot. 2005; 68(7):1467-71. DOI: 10.4315/0362-028x-68.7.1467. View

3.
Gattuso A, Gianfranceschi M, Sonnessa M, Delibato E, Marchesan M, Hernandez M . Optimization of a Real Time PCR based method for the detection of Listeria monocytogenes in pork meat. Int J Food Microbiol. 2014; 184:106-8. DOI: 10.1016/j.ijfoodmicro.2014.04.015. View

4.
Rossmanith P, Krassnig M, Wagner M, Hein I . Detection of Listeria monocytogenes in food using a combined enrichment/real-time PCR method targeting the prfA gene. Res Microbiol. 2006; 157(8):763-71. DOI: 10.1016/j.resmic.2006.03.003. View

5.
Schirmer B, Langsrud S, Moretro T, Hagtvedt T, Heir E . Performance of two commercial rapid methods for sampling and detection of Listeria in small-scale cheese producing and salmon processing environments. J Microbiol Methods. 2012; 91(2):295-300. DOI: 10.1016/j.mimet.2012.08.013. View