Methods and Media to Isolate and Enumerate Listeria monocytogenes: A Review

Abstract

Although long known to be harmful to livestock, Listeria monocytogenes has only recently been recognized as a serious food-borne pathogen in humans. Isolation of this organism from contaminated foods is often difficult due to the presence of naturally occurring microflora. Methods used to isolate L. monocytogenes have included cold incubation of samples, use of oblique lighting to examine the color of colonies, use of selective enrichment and plating media, and techniques in molecular biology. All of these methods have inherent disadvantages. A brief review of the methods and media used by various workers is presented in this paper.