To examine whether ATP in microbial cells could survive a thermal treatment, changes in microbial ATP content during the heat treatment were studied with a bioluminescent assay. The ATP content in
Escherichia coilcell lysate did not decrease when heated at 90°C for up to 10 min. When cell suspensions of
E. coli, Klebsiellasp.,
Staphylococcus aureus, and
Saccharomyces cerevisiaewere heated at 58°C, the content of the whole cell suspension ATP, ATP
w, slightly decreased to a certain level. The viable cells of the suspensions measured by a plate count method were rapidly inactivated. Changes in the contents of ATP
W, ATP
c (cell fraction), and ATP
f (cell filtrate fraction) of microbial cell suspensions during the heating process at 58°C were then studied. The contents of ATP
w and ATP
c gradually decreased for all organisms. The increase in the contents of ATP
f for
E. coliand
Klebsiellasp. showed that the intracellular ATP would leak out. When
E. coilcells were heated at various temperatures of 66-54°C, the content of ATP
w decreased to a similar level at these temperatures. The contents of ATP
c and ATP
f approached to certain levels, which were temperature dependent.
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