Detection of Listeria monocytogenes cells in food based on SD-PMA-ddPCR

Abstract:

[Objective] A method to detect live Listeria monocytogenes cells was researched in the paper. [Methods] Propidium monoazide (PMA) permeated in the injured cells which were treated by sodium deoxycholate (SD), then PMA and DNA conducted covalent cross-linking reaction. Finally, bacterial genome DNA was extracted to detect by ddPCR. [Results] 0.1% SD and 5.0 mg/L PMA could inhibit the DNA PCR amplification of 108 CFU/mL dead L. monocytogenes cells. Only live L. monocytogenes cells were detected by SD-PMA-ddPCR even in the existence of dead L. monocytogenes cells in the chicken. The detection limit is 2.0 copies/20 μL. SD-PMA-ddPCR showed better accuracy and stability. [Conclusion] SD-PMA-ddPCR showed huge potential in foodborne pathogenic bacteria detection.