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Loop-mediated isothermal amplification (LAMP) coupled with bioluminescence for the detection of Listeria monocytogenes at low levels on food contact surfaces

Mikš-Krajnik, Marta, Lim, Hazel Sin Yue, Zheng, Qianwang, Turner, Matthew, Yuk, Hyun-Gyun
Food control 2016 v.60 pp. 237-240
Listeria monocytogenes, bioluminescence, fish industry, food contact surfaces, inoculum, loop-mediated isothermal amplification, polyethylene, smoked salmon, stainless steel
A commercial loop-mediated isothermal amplification (LAMP) based system with bioluminescence, named as 3M™ Molecular Detection Assay (MDA), was validated for the detection of Listeria monocytogenes (3-strain cocktail) at low levels (100, 101, 102 CFU/100 cm2) inoculated on stainless steel (SS) and polyethylene (PE) surfaces, with and without (w/o) organic load (OL) of cold-smoked salmon homogenate by comparing with a standard ISO method as reference. The results of this study revealed that a commercial LAMP-based method performed equally effective compared with ISO method at inoculum levels of 100 and 102/100 cm2, showing 100% specificity and sensitivity, respectively. At 101 CFU/100 cm2, a slight reduction in the effectiveness of LAMP-based method was observed most likely due to the use of single enrichment step in the procedure of LAMP-based method. The LAMP-based method was shown to be rapid and reliable detection technique for L. monocytogenes present at low numbers on food processing surfaces, regardless of organic residues, and can be applicable in seafood industry.