Killing E. coli by heating at lethal temperatures 72 C evidently
results in few if any of the dead cells becoming permeable to PMA,
presumably because the barrier properties of the outer membrane
is not compromised (Merritt and Donaldson, 2009; Nikaido, 2003).
However, it appears that in large fractions of the cells killed by
heating at such temperatures, the outer cell membrane is sufficiently
damaged to allow it to be disrupted, and rendered permeable
to PMA by treatment with deoxycholate. The presence of dead