Influence of stress and growth conditions on individual lag time distributions of Listeria monocytogenes.

摘要

The effects of 9 common food industry stresses on individual lag time (lag) distribution of L. monocytogenes were determined. The distributions of lag obtained in a single regrowth condition revealed that there was a noticeable difference in response to the stresses encountered by L. monocytogenes cells. The applied stresses led to significant changes in the shape, mean and variance of lag distributions (in a single regrowth condition). Then, the influence of regrowth conditions on lag distribution and on the probability to initiate growth were examined for L. monocytogenes cells previously subjected to a representative stress situation of the dairy processing. A linear relation was observed between means of lag and their standard deviation. A decrease in the probability of initiating growth for stressed cells was also observed as growth conditions became unfavourable. These results suggest that stress-induced variability may be important in determining the reliability of predictive microbiological models..