Induction and PMA-qPCR detection of Listeria monocytogenes in viable but non-culturable state

Under the condition of 9% ( w /v) NaCl, the induction of “viable but non culturable” ( VBNC) Listeria monocytogenes was undertaken by investigating two factors, temperature and pH. In order to compare the changes of bacteria state and numbers caused by different inducing conditions, the LIVE/DEAD  BacLightTM Bacterial Viability Kit was used for enumeration of total cells and viable cells. The results showed that all viable Listeria monocytogenes were induced into the VBNC state at 2℃, pH6.0.PMA- qPCR was proposed to detect the Listeria monocytogenes experienced different inductions.It was indicated that PMA-qPCR was an effective method to detect viable Listeria monocytogenes even if undering the dead cells background.