La mantequilla de mani es un producto con un alto contenido de grasa y reducida actividad de agua, y que hasta finales de los noventa no habia sido vinculado con la transmision de Salmonella. El objetivo de este trabajo fue determinar el tiempo de sobrevivencia de dos poblaciones de Salmonella enterica inoculadas en mantequilla de mani y almacenadas a temperatura ambiente. Se evaluo el recuento total aerobio, recuento de hongos filamentosos y levaduras y presencia de Salmonella spp. en tres lotes distintos de cuatro marcas comerciales de mantequilla de mani, obtenidos en los principales supermercados del area metropolitana de San Jose, Costa Rica. Tambien, se evaluo la sobrevivencia de una densidad celular alta (107 UFC/ml) y baja (103 UFC/ml) de Salmonella Enteritidis ATCC 13076, inoculada en muestras de mantequilla de mani e incubadas a temperatura ambiente. Los recuentos de la flora nativa fueron bajos, de la misma manera que todas las muestras fueron negativas para la presencia de Salmonella spp. Salmonella enterica inoculada a baja concentracion mostro un valor inicial maximo de 2,78 log10 UFC/g en las cuatro marcas comerciales evaluadas, y no fue capaz de sobrevivir luego de dos semanas de incubacion. Las muestras inoculadas con una alta concentracion de S. enterica presentaron una disminucion constante del numero de bacterias durante las seis semanas de incubacion, siendo esta diferencia mayor en las primeras dos semanas.
Peanut butter is a product with high content of grease and reduced water activity. This product had not been associated with the transmission of Salmonella until the late nineties. The aim of this work was to determine the survival time of two populations of Salmonella enterica inoculated in peanut butter and stored at room temperature. Total aerobic plate count, molds and yeast count and the presence of Salmonella were determined in three different lots of four commercial brands of peanut butter, three imported and one of national production, obtained from the main supermarkets of the metropolitan area of San Jose, Costa Rica. Also, the survival of a high (107 UFC/ml) and low cell density (103 UFC/ml) of Salmonella Enteritidis ATCC 13076, inoculated into peanut butter samples and incubated at room temperature during the storage time was evaluated. The counts of the native flora were low; as well as all samples were negative for the presence of Salmonella spp. Samples inoculated with the low concentration of Salmonella enterica showed an initial count lower than 2.78 log10 UFC/g in the four different brands evaluated and could not survive longer than two weeks. Samples inoculated with a high concentration of Salmonella enterica showed a constant decrease in the number of bacteria for the six weeks of the study with higher reductions observed during the first two weeks.