Listeria Enrichment Broth is used for selective enrichment of Listeria spp and is not intended for use in the diagnosis of disease or other conditions in humans.

Listeria monocytogenes, first described in 1926 by Murray, Webb, and Swann, is an extensive problem in public health and food industries. This organism has the ability to cause human illness and death, particularly in immunocompromised individuals and pregnant women. Epidemiological evidence from outbreaks of listeriosis has indicated that the principle route of transmission is via consumption of foodstuffs contaminated with Listeria monocytogenes. Implicated vehicles of transmission include turkey frankfurters, coleslaw, pasteurized milk, Mexican style cheese, and pate. Listeria spp. are ubiquitous in nature, being present in a wide range of unprocessed foods as well as in soil, sewage, and river water.

Listeria Enrichment Broth is based on the formula developed by Lovett et al. in which Tryptic Soy Broth is supplemented with Yeast Extract for optimum growth. Listeria spp. grow over a pH range of 5.0 – 9.6, and survive in food products with pH levels outside these parameters. Listeria spp. are microaerophilic, Gram-positive, asporogenous, non-encapsulated, non-branching, short, motile rods. Motility is pronounced at 20°C. Identification of Listeria is based on successful isolation of the organism, biochemical characterization, and serological confirmation.