The role of temperature factors in the epidemiology of listeriosis.

A total of 5000 samples were examined for Listeria monocytogenes, and 117 strains had been isolated. Out of these, 36 strains were selected according to their low virulence. An increasing virulence could be observed, when they were cultured on optimal media at 4 degrees C, with inoculations at every third week. This increased virulence caused by temperature factors, can have an important role in the epidemiology of listeriosis.