This bacterial genus includes the pathogen Listeria monocytogenes, as well as, six non-pathogenic species (L. grayi, L. inocua, L. ivanovii, L. seeligeri, and L. welshimeri). Preventing contamination of products with L. monocytogenes requires effective sanitation of food contact and non-contact surfaces in the manufacturing environment. Monitoring the environment for the presence of all Listeria spp. helps to ensure that the sanitation program is effective and will prevent the establishment of L. monocytogenes.