| Resumen: | Objetivo: Determinar la presencia de L. monocytogenes en quesos frescos de producción artesanal expendidos en los mercados de Ica durante el periodo enero - marzo de 2003. Material y Métodos: De la totalidad de los puestos que expenden queso fresco artesanal en los mercados Santo Domingo, Alejandro Toledo, San Antonio y Modelo, se evaluaron 74 muestras teniendo como unidad muestral 200 g según la Norma Técnica Peruana ISO 28329-1. El procesamiento, aislamiento e identificación se realizó de acuerdo con la metodología recomendada por el manual de bacteriología analítica de la Food and Drug Administration (FDA). Resultados: De las 74 muestras, 3 (4,05 por ciento)presentaban L. monocytogenes, y de ellas, una muestra correspondió al mercado Alejandro Toledo y 2 muestras al mercado Modelo. Se logró aislar 28 cepas de las cuales 6 (21,4 por ciento)correspondieron a L. monocytogenes, y 22 (78,6 por ciento) a otros microorganismos como Lactococcus lactis ss lactis, Enterococcus spp. y Bacillus spp. No se logró aislar L. monocytogenes en los mercados Santo Domingo y San Antonio; sin embargo, en el mercado Alejandro Toledo se aisló una cepa y en el mercado Modelo, se aislaron 5 cepas, lo cual demuestra la presencia significativa de L. monocytogenes sólo en el mercado Modelo. Conclusiones: Existe L. monocytogenes en quesos frescos de producción artesanal, representando un riesgo potencial para la población consumidora. (AU)^iesObjective: To determine the presence of L. monocytogenes in home made non-pasteurized cheese sold in Ica district markets during the period from January to March, 2003. Material and Methods: 74 samples were assessed from all the vendor places in Santo Domingo, Alejandro Toledo, San Antonio, and Modelo markets, and the sampling unit was 200 g, according to the Peruvian technical Specification ISO 28329-1. Processing, isolation, and identification were performed according the methodology recommended by analytical bacteriology manual edited by the US Food and Drug Administration (FDA). Results: Of the 74 samples, 3 (4.05 percent) had L. monocytogenes, one of them from Alejandro Toledo market and the other two were from Modelo market. Overall, 28 bacterial strains were isolated, 6 (21.4 percent) of them were identified as L. monocytogenes, and 22 (78.6 percent) had other microorganisms, such as Lactococcus ss lactis, Enterococcus spp., and Bacillus spp. No L. monocytogenes strains were isolated from Santo Domingo and San Antonio markets; however, in Alejandro Toledo market one strain was found, and in Modelo market 5 strains were isolated, which proves the significant presence of L. monocytogenes only in Modelo market. Conclusions: There is presence of L. monocytogenes in home made non pasteurized cheese, which represents a potential risk for the consumer population. (AU)^ien.
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