1. Introduction
Most studies in predictive mycology have been concerned with
the effect of environmental factors, principally water activity,
temperature, pH, and modified atmospheres, on fungal germination,
fungal growth, and mycotoxin production, at steady-state
conditions (Dantigny and Bensoussan, 2013). Unfortunately, very
little information on modeling these biological responses under
fluctuating conditions is available. The lack of experimental devices
allowing automatic monitoring of growth and germination, in
addition to the use of solid media, may explain this shortage of
experiments carried out under transient conditions (Dantigny and
Nanguy, 2009). Steady-state is a very poor assumption in the
environment where non constant conditions prevail. For example
the effects of fluctuating moisture and temperature conditions on
growth and viability of fungi in building materials were investigated
(Pasanen et al., 2000). It has been reported that moisture
conditions on the surface were critical for the development of
fungal growth in a material, because fungi grow on the surface, but
the medium can also serve as a reservoir of water. Therefore, it
appeared that mass transfer phenomena should be taken into account
for explaining the experimental results. Sedlbauer (2001)
developed a biohygrothermal model to describe the effect of the
humidity available at certain temperatures on the germination of
fungal spores. The water content in the spore was recalculated
every hour by the calculation of the ambient humidity in dependence
of transient boundary conditions. When a critical water
contentwas achieved inside the spore, germinationwas completed.
Fluctuating conditions were also examined in the fields of plant
pathology. The effect of temperature on the length of the incubation
period of rose powdery mildew was studied (Xu, 1999). It
was shown that models derived from constant temperature