There was no TTD for most of the
microbes in the pasta sauce but the low pH (4.2) would explain the
absence of growth. Interestingly, there was approximately a
3 log10 CFU increase for the E. coli and S. enteriditis strains and a TTD
was recorded for the E. coli in the pasta sauce. These results indicate
these strains were at least more tolerant of the acidic environment
than expected for these microorganisms. In addition, the
L. monocytogenes strain was not detectable by impedance in four
(Bechamel sauce, pasta sauce, chocolate sauce and UHT milk) of the