The Listeria genus is ubiquitous in our environment, and while most species do not cause disease in humans, L. monocytogenes does pose a human health threat, especially in immunocompromised individuals and pregnant women. Listeria is commonly found in food manufacturing environments and outbreaks have been reported from many different food sources, including meats and dairy products. Listeria presents a challenge in food production environments because is able to grow in environments ranging from pH of 5.0 – 9.6 and at refrigerated temperatures.
UVM is a modified formula of the Listeria Enrichment Broth described by Donnelly and Baigent. A blend of casein peptone, enzymatic digest of animal tissue, beef extract, and yeast extract provide the nitrogen sources needed for growth, along with vitamins and minerals to support cellular function. Phosphate salts act as buffering agents, while sodium chloride maintains osmotic balance. Nalidixic Acid and Acriflavin inhibit Gram-negative bacteria and Gram-positive bacteria other than Listeria.