Listeria is a unique organism because, unlike many other bacteria, Listeria thrives well in cold temperatures below 41°F. Furthermore, the mortality rate for Listeria is significantly higher than that of more common bacteria associated with foodborne illnesses, such as Salmonella.
Although illnesses such as Salmonella are more prevalent, Listeria is a more dangerous bacterium and is oof special concern to pregnant women who may be at significant risk of spontaneous abortion due to this illness.