Developed by Donnelly and Baigent, UVM Modified Listeria Enrichment Broth medium is used for the selective isolation and enrichment of Listeria spp. from clinical specimens and food. Within the formula, the high salt tolerance of Listeria is used to inhibit the growth enterococci, Nalidixic acid (20 mg/L) to inhibit Gram-negative microorganisms and Acriflavin to inhibit Gram-positive bacteria. The Esculin is utilized by Listeria spp. and results in the blackening of this medium.