Initial numbers, serovars and phagevars of Listeria monocytogenes isolated in prepared foods in the city of Barcelona (Spain)

A total of 1100 samples of prepared foods purchased in restaurants and delicatessen shops in the city of Barcelona was examined for the presence of Listeria. L. monocytogenes was more frequently isolated from foods intended to be consumed without further cooking (9.3%) than from foods intended to receive further cooking prior to consumption (2.9%). A quantitative study, carried out with 773 samples, yielded 1% of samples with numbers of L. monocytogenes higher than 100 CFU/g. Strains of L. monocytogenes belonged to serovar 4b (36.3%), 1/2a (29.5%), 1/2b (22.7%) and 1/2c (11.3%). L. monocytogenes serovar 4b phagevar 3274: 2671 (6 of 11) was prevalent among the strains studied.