3.3. Kinetic parameters of survival
There is often confusion about the difference between
specific growth rate m and growth rate k. Both
parameters are reflections of an exponentially increasing
population. The constant m is a measure of the specific
or instantaneous growth rate and it is the slope of a
straight line. Thus, this constant measures the rate of
growth when it is maximal (the growth rate ‘‘per
organism’’), but does not reflect the behaviour of the
population over a period of time. In contrast, the k
constant is an average value for the population growth
rate over a finite period of time. These concepts can be
similarly applied to the death curves and their parameters,
the specific death rate m0 and the death rate k0
.
The linear regression equations and the regression
coefficients obtained from fermentation and storage
periods of E. coli O157:H7 and E. coli CECT 516 are
shown in Table 1. An increase in the values of m related
with the increase of the temperature of fermentation was
observed: from 0.0731 h1 (LIM) to 0.3229 h1 (SIM) in