Resumo

MARTINO, Tamara K et al. Incidence of Listeria spp: in fresh vegetables. Rev Cubana Salud Pública [online]. 2008, vol.34, n.4. ISSN 0864-3466.

Introduction Listeria monocytogenes is a pathogen that can be vegetable-borne. Its incidence on this type of food is unknown in Cuba. Objectives To evaluate the presence of Listeria spp. and the effect of cleaning methods in fresh vegetables on sale in the City of Havana. Methods Eighty six samples were analyzed by using Rapid Test Oxoid (1999) and the traditional ISO 11290-1 (1996) and ISO 11290-2 (1998) methods. Also additional biochemical tests and cold enrichment to 4 ºC, were made. Health quality indicators, coliforms (NC ISO 4832/2002) and faecal coliforms (NC 38-02-14/1989) were determined. The presence or absence of bacteria after the cleaning process was determined in samples positive to Listeria spp. and in contaminated samples with Listeria monocytogenes. Results Listeria spp. was detected by the rapid test in lettuce, carrot, cabbage and scallion; Listeria innocua was isolated in the last three ones at<10² UFC/g concentrations. These samples showed coliforms at>10³/g concentrations and two of them faecal coliforms at>10²/g. After the cleaning process, no bacteria was detected in previously L. innocua positive carrot and scallion samples whereas in lettuce and carrot samples innoculated with L. monocytogenes and cleaned, the level of this microorganism was just reduced. It was confirmed that the traditional cleaning process to eliminate L. monocytogenes is not enough unless this bacterium is present at low concentrations. Conclusions The only isolated species L. innocua was not a health risk. Listeria spp.-positive samples did not have good sanitary quality.

Palavras-chave : Listeria; Listeria monocytogenes; vegetables; coliforms; faecal coliforms.