UVM Broth acc. to USDA/FSIS

UVM Broth is used for the selective enrichment of Listeria spp from food samples and is a modification of the formula described by Donnelly and Baigent. The USDA/FSIS method states to add 25 mL liquid or 25 g sample to 225 mL UVM Broth. For environmental sponges, add 225 mL of UVM Broth to each bagged sponge sample. After incubation, a portion of the enrichment mixture is added to an enrichment broth or plated onto the final isolation agar. Identification of Listeria is based on successful isolation of the organism, biochemical characterization, and serological confirmation. Enzymatic Digest of Casein, Enzymatic Digest of Animal Tissue, Beef Extract, and Yeast Extract provide nitrogen, vitamins, and minerals in UVM Broth. The Phosphates are the buffering agents, Sodium Chloride maintains osmotic balance. Nalidixic Acid inhibits growth of Gram-negative organisms. Acriflavin inhibits Gram-positive bacteria. Esculin is hydrolyzed by Listeria spp. The high salt tolerance of Listeria is used to inhibit growth of enterococci.