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| Detection of Listeria monocytogenes in Poultry and Livestock Meat by Propidium Monoazide-Hydroxynaphthol Blue-Loop-Mediated Isothermal Amplification Method |
| DAI Xiaofang, CHEN Qiong, DONG Huaxia, XIANG Chunyan, YU Weiming, LI Juan |
| Wuhan Institute for Food and Cosmetic Control, Wuhan 430012, China |
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Abstract Using propidium monoazide (PMA) treatment and hydroxynaphthol blue (HNB) staining combined with loopmediated isothermal amplification, a rapid and visual detection method (PMA-HNB-LAMP) for Listeria monocytogenes was established in this study. The optimization of experimental parameters showed that a final PMA concentration of 5.0 μg/mL, incubation time of 15 min and exposure time of 15 min could restrain DNA amplification of 105 CFU/mL dead cells but not of live cells. A final HNB concentration of 210 μmol/L could give results visible to the naked eyes. The sensitivity of the PMAHNB-LAMP method was 2.4 × 102 CFU/mL for pure bacterial culture. The detection limit for artificially contaminated meat was 2.3 × 104 CFU/mL. Using the national standard method, PMA-HNB-LAMP and HNB-LAMP, the detection rates of L. monocytogenes in 20 meat products available on the market were 5%, 10% and 20%, respectively. PMA-HNB-LAMP is superior to traditional LAMP in avoiding false-positive results to a certain extent, and it has the advantages of simple operation and strong visibility.
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2020, Vol. 34 
