Detection of Listeria species and Listeria monocytogenes using polymerase chain reaction

Five oligonucleotide sequences are described that were used as primers in the polymerase chain reaction (PCR) to amplify specific sequences from Listeria DNA. When all five primers were used in combination, three PCR products were possible; a Listeria specific product that occurs with DNA from any Listeria sp., a Listeria monocytogenes specific product that occurs only in the presence of DNA from this organism and a universal product that is found using DNA from any bacterial source. The occurrence of these PCR products was used as a diagnostic test on bacteria isolated from various food samples to detect Listeria sp. and L. monocytogenes.