The prevalence and molecular characterization of listeria monocytogenes in corn silage, feces and bulk tank milk samples in dairy cattle farms in

Abstract

The objective of this study was to investigate the prevalence and molecular characterization of Listeria monocytogenes in corn silage, feces and bulk tank milk (BTM) samples. The samples (n=150/each; 450 in total) were obtained from dairy cattle farms and analyzed for Listeria spp. and L. monocytogenes. The isolates were identified by using biochemical tests. Serotyping was done by using Polymerase Chain Reaction (PCR). Also the source and possible contamination routes with L. monocytogenes were determined by using Pulsed Field Gel Electrophoresis (PFGE). The percentages of L. monocytogenes detected in the silage, feces and milk samples were 4%, 2.4% and 2.4%, respectively. There were 10 different PFGE types and 4 serotypes of the 14 isolates. The isolates of 14 L. monocytogenes were distributed into four serogroups as "1/2a, 3a" (n=6),"1/2b, 3b" (n=3) "1/2c, 3c" (n=2), and "4b" (n=3). According to the method of PFGE, L. monocytogenes strains obtained from the samples were determined to be related to each other. Although the prevalence of L. monocytogenes is low in those samples, it is a serious risk in terms of food safety and public health.