Isolation of Listeria monocytogenes from Food and Water: Official and Experimental Protocols

Listeria monocytogenes is frequently encountered in foods but often at low concentrations and typically in the presence of other microbiota, including nonpathogenic Listeria spp. The potential of L. monocytogenes to cause severe human disease mandates sensitive, accurate, and rapid detection in foods. Isolation of L. monocytogenes from foods is critical, not only for routine surveillance, but also for epidemiologic investigations. Isolation of the pathogen from water (especially surface water used for irrigation) is similarly important, as produce has been implicated in listeriosis outbreaks and contaminated water can be involved in contamination of produce. This unit provides basic protocols for the isolation of L. monocytogenes from foods and water.