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Development and evaluation of a loop-mediated isothermal amplification (lamp) method for detecting Listeria monocytogenes in raw milk

Wang, D., Huo, G., Ren, D., Li, Y.
Journal of food safety 2010 v.30 no.2 pp. 251-262
raw milk, microbial detection, Listeria monocytogenes, food pathogens, bacterial contamination, food contamination, polymerase chain reaction, gene amplification
The performance of a Loop-mediated isothermal amplification (LAMP) assay for detecting food-borne pathogen Listeria monocytogenes was presented in this paper. Three pairs of primers were specially designed for recognizing eight distinct sequences of iap gene (P60 extracellular protein, invasion associated protein IAP). Time and temperature conditions for amplification of L. monocytogenes were optimized to be 40 min at 63C. Detection limit level for artificially contaminated raw milk samples by the LAMP assay was 186 cfu/mL corresponding to 8-10 cells per reaction tube, while the detection level by conventional PCR was 1.86 x 10⁵ cfu/mL. Data on natural raw milk samples indicated that the LAMP method was highly specific and sensitive, giving 91.67% concordance with the ISO 10560 reference method for the samples without enrichment and 100% concordance after enrichment. The LAMP method in this paper provided a powerful tool with the specificity, sensitivity and rapidity for detection of Listeria monocytogenes in raw milk.