OCCURRENCE OF LISTERIA SPECIES IN PREPACKED RETAIL SANDWICHES

A survey of 725 prepacked sandwiches was conducted examining for the p resence on enrichment, and by plate count, of Listeria species. Sandwi ches were found to contain Listeria sp. more frequently than their com ponent foods. Chicken, beef and bacon fillings were associated with mo re frequent isolation. Salad also was associated with more frequent is olation, but the increase was not significant. On enrichment, over 15% of sandwiches contained Listeria species. L. innocua and L. monocytog enes were the only species isolated by plate count at numbers greater than or equal to 100 cfu/g (1.5% of total samples). Potentially hazard ous levels of L. monocytogenes (defined as greater than or equal to 10 (3) cfu/g) were found in two sandwiches examined (0.3%), indicating th at although Total Viable Counts (TVCs) may often be high, the risk of listeriosis to vulnerable individuals from sandwiches is relatively lo w. It is important to distinguish the risk of consuming potentially ha zardous levels of a pathogen in food from the risk of contracting illn ess as a result of such an event.