Effects of heat-processing regime, pH, water activity and their interactions on the behaviour of Listeria monocytogenes in groundpork. Modelling the boundary of the growth/no-growth areas as a function of pH, water activity and temperature
Résumé
The influence of four heat-processing regimes and a storage phase on the behaviour of Listeria monocytogenes in ground pork was studied. The effects of pH and water activity (aw) were also tested. During the heat process phase, aw, the heat-processing regime and its interactions with pH or aw, had a significant effect on the behaviour of L. monocytogenes. During the storage phase, all parameters tested and their interactions had significant effects. Nevertheless, the area in which the growth of L. monocytogenes was observed at the end of the experiment was not influenced by the heat-processing regime tested. On the contrary, pH, aw and their interactions had significant effects on Listeria behaviour. The boundary of the growth area delimited by environmental conditions where growth was higher than 1.0 Log CFU g)1 from those where growth was lower than this limit was correctly predicted by Augustin’s model.