3. Results and discussion
galacturonic acid (ICN Biomedicals Inc., OH, USA)
4 g/ l and yeast extract (Biokar Diagnostics, France) 3.1. Primary model
2 g/ l, pH 7. Experiments were carried out in 250-ml
flasks containing 50 ml medium. Initial biomass 3.1.1. Microbial growth
1 3 concentration was in a range of 10 –3.10 cfu / ml. Predictive microbiology approach consists in de-
Biomass concentration was measured by counting veloping models to describe bacterial growth kinetics
cell colonies (cfu /ml) on nutrient agar plates, incu- with three parameters: the maximal growth rate m
21 bated for 48 h at 308C. (h ), the lag phase period L (h) and the maximal
To establish temperature effect on growth and biomass quantity N (cfu /ml). The objective is max
damage parameters, cultures were incubated at 0, 4, essentially to estimate m and L as accurately as
7 and 108C, with sub-culture in synthetic medium at possible in order to evaluate shelf-life of foods. The