SHAMA, G., 2005. Estimating the maximum specific growth rate from microbial growth curves : definition is everything. Food microbiology, 22(6), pp. 491-495
The maximum specific growth rate (μmax) is an important parameter in modelling
microbial growth under batch conditions. However, there are two definitions of this
growth parameter in current use and some of the comparisons of data made in the
literature fail to acknowledge this important fact.
We compared values of μmax obtained by applying the Gompertz, logistics and
Baranyi-Roberts models to experimental data on the growth of Listeria
monocytogenes and Listeria innocua using both absorbance and viable counts
measurements of cell concentration. All three models fitted the experimental data
well, however, the values of μmax obtained using the Gompertz and logistic models
were similar to each other but substantially different from that predicted by the
Baranyi-Roberts model. The latter growth model was used to derive a second
estimate of μmax based on the slope at the inflection point of the growth curve
function; this value was in closer agreement with those obtained using the Gompertz
or logistic models. Conditions were identified when values of μmax based on different
definitions would converge towards one another.