Applying a generalized z -value concept to quantify and compare the effect of environmental factors on the growth of Listeria monocytogenes Original Research Article

The z -value concept, commonly used in thermal death kinetics of bacteria, is generalized for growth and for the situation when the modelled growth parameter is a non-linear function of several environmental variables. The (harmonic) mean of the generalized z -value in the region of interest is applied to quantify the ‘average’ effect of an environmental variable. This mean is used to compare the effect of temperature and atmospheric carbon dioxide on the growth of Listeria monocytogenes.