Prevalence of Listeria monocytogenes in Ready-to-Eat Foods Sampled from the Point of Sale in Wales, United Kingdom

A survey of Listeria in ready-to-eat food took place in Wales, United Kingdom, between February 2008 and January 2009. In total, 5,840 samples were taken and examined for the presence of Listeria species, including L monocytogenes. Samples were tested using detection and enumeration methods, and the results were compared with current United Kingdom guidelines for the microbiological quality of ready-to-eat foods The majority of samples were negative for Listeria by both direct plating and enriched culture Seventeen samples (0 29%) had countable levels of Listeria species (other than L monocytogenes). and another 11 samples (0.19%) had countable levels of L monocytogenes. Nine samples (0 15%) were unsatisfactory or potentially hazardous when compared with United Kingdom guideline limits; six (0 10%) were in the unsatisfactory category (>100 CFU/g) for Listeria species (other than L monocytogenes), and three (0.05%) were in the unacceptable or potentially hazardous category (>100 CFU/g) for L monocytogenes All three of these samples were from sandwiches (two chicken sandwiches and one ham-and-cheese sandwich). The most commonly isolated serotype of L. monocytogenes was 1/2a This survey was used to determine the current prevalence of Listeria species and L monocytogenes in ready-to-eat foods sampled from the point of sale in Wales.