Listeria monocytogenes

Listeria monocytogenes was discovered as a pathogen of animals and humans in the 1930s. As far as humans are concerned the organism was initially identified as a cause of abortion in early pregnancy, stillbirth, or of septicemia after an uneventful birth. Ecological surveys have demobstrated that Listeria in general, and L. monocytogenes in particular, are naturally occurring in a wide variety of domestic animals, particularly sheep and chickens. L. monocytogenes has four attributes: the alleged elevated heat resistance, the ability for relatively rapid growth at refrigeration temperatures, a marked tolerance of reduced pH values, and growth in the presence of over 5% sodium chloride.