Use of propidium monoazide and quantitative PCR for differentiation of viable Escherichia coli from E. coli killed by mild or pasteurizing heat treatments

► Propidium monoazide (PMA) inactivates for PCR DNA in cells with damaged membranes. ► DNA in E. coli killed by mild heat treatments is not inactivated by PMA. ► Incubation with deoxycholate renders DNA in those cells susceptible to PMA. ► Live E. coli at ≥1% among live and dead cells can be enumerated by real-time PCR.