Abstract

Listeria monocytogenes is an important agent of foodborne disease, showing low prevalence but highmortality. There is evidence that vegetables are important vehicles of transmission, especially thoseminimally processed (fresh, fresh-cut vegetables under modified atmosphere packaging (MAP) or frozen)and directly exposed to consumers. The aim of this work was to detect and enumerate viable L.mono-cytogenes cells by culture and molecular methods from vegetable foods.A total of 191 vegetable samples (fresh, frozen and fresh-cut under modified atmosphere packaging)were studied. L. monocytogenes was detected and identified by selective plating, PCR and DVC-FISH.An isolation rate of 4.19% was obtained by culture, with a higher incidence in frozen vegetables. Sixisolates belonged to serotype 1/2a and 2 to 4b. Counts were below <100 cfu/g for the eight positivesamples, according to the food safety criteria established for the RTE by Commission Regulation EC No1441/2007.Multiplex PCR method yielded a greater number of positive samples (10.47%). DVC-FISH techniquedetermined that viable cells of L.monocytogenes were present in 32.98% of the samples, containing up to4.97 log10viable cells/g.