Occurrence and characteristics of Listeria monocytogenes in ready-to-eat food from retail market in the Czech Republic

Abstract

The study objectives were to test ready-to-eat food from the retail market in the Czech Republic for the presence of L. monocytogenes and, based on typing methods, to investigate probable causes of contamination. A total 2180 samples of ready-to-eat food (meat, dairy, fish, delicatessen and confectionery products and fresh fruit and vegetables) were analysed qualitatively and quantitatively. L. monocytogenes isolates were characterised by serotyping and macrorestriction analysis after digestion with the restriction enzyme AscI. In 2004–2008 L. monocytogenes was most often detected in delicatessen (5.2%), meat (3.4%) and dairy products (1.8%). In the analysed samples, L. monocytogenes was mostly present at counts lower than 102 CFU/g. Only in 2004, higher counts of L. monocytogenes were found in two heat-processed meat products (103 CFU/g). The obtained macrorestriction patterns helped in tracing the source of contamination and routes of the spread of L. monocytogenes in the manufacturing plant and retail market.