ABSTRACT
Models used to describe increases in the bacterial popula-
tion in foods are generally of two types: models that predict
the increase in bacterial number over time and models that
estimate the probability of growth occurring at a particular
point in time. For purposes of this entry, we will refer to the
former as “population growth models” and the latter as
“probability-of-growth models.” Both types are capable
of describing the influence of one or more environmental
variables (i.e., temperature, pH, water activity, preserva-
tive concentration, and so on) on the variable of interest
(bacterial concentration or probability of a concentration
increase). Both types of models are used for both food-
borne pathogens and food spoilage organisms.
