The prevalence, counts and genetic diversity of Listeria monocytogenes in ready-to-eat (RTE) vacuum and
modified atmosphere packaged meat and fish products was studied in Estonia. Within two consecutive
years 370 RTE food samples were collected at retail level from which 11% were found to be positive for L.
monocytogenes. Contamination was higher among RTE fish products (17%) than in RTE meat products
(6%). Generally, the counts of L. monocytogenes in positive products remained under ten colony forming
units (CFU) per gram of product. Only 1.6% of the RTE meat and fish products contained L. monocytogenes
in range of 10e100 CFU/g and 0.3% more than 100 CFU/g at the end of shelf-life. The food category
containing highest L. monocytogenes prevalence was RTE lightly salted fish products with the prevalence
of 32%. Only one (0.3%) RTE food sample exceeded the 100 CFU/g food safety criterion set out in the EU
Regulation 2073/2005. Pulsed-field gel electrophoresis (PFGE) characterization of the isolates showed an
overall similarity higher than 70%, and nine clusters based on 100% similarity were revealed. PFGE
genotyping revealed that the few predominant pulsotypes were associated with particular food plants.