Sources of enterococci in Idiazábal-type cheese.

Enterococci are a ubiquitous group and are natural constituents of the intestinal flora of nearly all animals and humans and can reach high levels in a variety of farmhouse cheeses. The purpose of this study was to determine the origin of the different enterococcal strains present in cheeses at different stages of ripening by typing the enterococci isolated from the raw milk, the cheeses, the cheesemaking environment, and from the faecal matter of the ewes and humans associated with cheese production. The potential presence of vancomycin-resistant enterococci (VRE) at all stages of the process and in the cheeses was also considered. The study was carried out at two separate cheesemaking dairy plants, and samples of the ewes' faeces, the shepherds' and cheesemakers' stools, teat cups, vat, brine, holding tank milk, vat milk, and the cheeses after brining and after 1, 15, and 60 days of ripening were collected. Cheesemaking procedures at the two plants were similar, yet the enterococcal levels and species observed differed at all the sample collection points, though E. faecalis predominated in all the milk and cheese samples. The traceability study performed for the species E. faecalis present at all the sample collection points suggested that the cheesemaker and the cheesemaking equipment were the source of the enterococci in the cheeses, though other possible non-faecal sources remain to be determined. VanC1 and vanC2/C3 enterococcal strains were isolated from the ovine faeces, teat cup, brine, and vat samples at cheesemaking dairy plant A, while only two vanC2/C3 strains were isolated from ovine faeces samples at dairy plant B. No VRE strains were detected in any of the milk or cheese samples.

Effect of lactobacillus adjunct cultures on the microbiological and physicochemical characteristics of Roncal-type ewes'-milk cheese.

The effect of two different experimental adjunct cultures composed of native facultatively heterofermentative lactobacilli (FHL) on the development of various groups of micro-organisms in Roncal-type ewes' milk cheese was studied. Four cheese batches were manufactured from raw milk (C), pasteurized milk (P), pasteurized milk and an adjunct culture of Lactobacillus paracasei (PP); and pasteurized milk and adjunct culture of Lactobacillus paracasei plus Lactobacillus plantarum (PPP). Retention of the two adjunct cultures in the cheeses was good, and population levels remained constant at around 10(7) cfu g(-1) of cheese throughout ripening. Levels of Enterobacteriaceae and enterococci fell off more abruptly in the batches made with the Lactobacillus adjunct cultures, suggesting competition between the added lactobacilli and those groups of micro-organisms. The inhibitory effect was greater for the adjunct culture composed of L. paracasei plus L. plantarum. Lactococcal levels were higher in the batches made with added FHL, which may be indicative of a synergistic effect between these two groups.

Gram-positive bacteria of marine origin: a numerical taxonomic study on Mediterranean isolates.

A numerical taxonomic study was performed on 65 Gram-positive wild strains of heterotrophic, aerobic, marine bacteria, and 9 reference strains. The isolates were obtained from oysters and seawater sampled monthly over one year, by direct plating on Marine Agar. The strains were characterized by 96 morphological, biochemical, physiological and nutritional tests. Clustering yielded 13 phena at 0.62 similarity level (Sl coefficient). Only one of the seven phena containing wild isolates could be identified (Bacillus marinus). A pronounced salt requirement was found in most isolates.

Effect of pasteurization of Ewe's milk and use of a native starter culture on the volatile components and sensory characteristics of roncal cheese.

The effect of pasteurization of milk and use of a native starter culture on the volatile components and sensory characteristics of a Spanish ewe's-milk cheese were examined. Three cheese batches were made, one from raw milk, another from pasteurized milk, and a third from pasteurized milk with an added native starter culture in addition to the commercial starter. Cheeses were analyzed at 1, 120, and 240 d of ripening. Analysis of the volatile components was by purge and trap connected to a gas chromatograph with a mass spectrometer and disclosed a total of 76 components belonging to the following chemical families: hydrocarbons, fatty acids, esters, sulfur and carbonyl compounds, and, in particular, alcohols. Pasteurization lowered the levels of certain volatile components, especially alcohols, aldehydes, and ketones. The cheeses made from pasteurized milk showed lower scores for attributes of characteristic taste and aftertaste, as well as a characteristic aroma at 240 d of ripening. These results suggest that the components present in higher concentrations in the cheeses made from the raw milk were necessary for development of characteristic Roncal cheese aroma. The new native starter culture tested did not exert a significant effect on any of the parameters considered, with the exception of certain isolated components, for which higher or lower quantities were recorded in the cheeses made with that starter culture, although the differences did not have a definite effect on the sensory characteristics of the cheeses.

Aerobic and facultative anaerobic heterotrophic bacteria associated to Mediterranean oysters and seawater.

A comparative study on the composition and seasonal fluctuations of the main heterotrophic bacterial groups and species isolated from Mediterranean oysters and their growing-seawater was carried out. For the study we used 574 strains isolated from Marine Agar (MA) and submitted to numerical analysis of phenotypic traits in previous studies, plus 323 isolates recovered on Thiosulphate Citrate Bile Sucrose (TCBS) agar from the same samples and identified in this study. Oyster samples were dominated by halophilic fermentative bacteria during most of the year with predominance of two Vibrio species, V. splendidus (at temperatures lower than 20 degrees C), and V. harveyi (at higher temperatures). On the contrary, Vibrio spp. was not the predominant microbiota of seawater, where most isolates had remained unidentified but corresponded to alpha-Proteobacteria, as shown by rDNA hybridization with phylogenetic probes in this study. Among the strict aerobes that could be identified, none of them showed a clear dominance, and many different groups were represented in very low percentages, in contrast with the major species from oyster samples. Shannon-Weaver diversity index revealed significant differences between both types of samples. No apparent seasonality was found in the distribution of seawater species, in sharp contrast with oyster-associated bacteria.

Conocimientos de la etiología y los factores de riesgo de los defectos congénitos en pediatría / Knowledge of Pediatricians concerning Causes and Risk Factors for Congenital Disorders

Objetivos: Determinar el grado de conocimiento de los pediatras en relación a la etiología, factores de riesgo y formas de prevención de los defectos congénitos. Estudio de diseño prospectivo observacional descriptivo, con muestreo no probabilístico de casos consecutivos. De los 117 médicos encuestados: 47% (n: 55) eran residentes, 48% (n: 56) pediatras, 4.2% neonatólogos (n:5), 0,8% médicos de familia (n:1). La proporción de respuestas correctas fue de 35/51 (68,6%). El 28,2% (n: 33) conoce la influencia de los defectos congénitos en la mortalidad infantil, el 44,4%(n: 52) la desconoce. La talidomida y las tetraciclinas fueron reconocidas como agentes teratogénicos por más del 80% de los encuestados, menos del 50% reconoció la acción teratogénica de la vitamina A, del acido valproico y del enalapril. Más del 80% reconoció como agente no teratogénico al acido fólico, al paracetamol y a la amoxicilina. El 80% indicó que no hay una dosis segura de ingesta alcohólica. Más del 80% identificó como factores de riesgo la consanguinidad, hijo previo malformado y la edad materna. El 56% y el 83% reconocieron inequívocamente la edad paterna y el tabaquismo materno como factores de riesgo respectivamente. El 95,7% reconoció la aparición del Síndrome de Down como relacionado a la edad materna, pero menos del 50% identifico a las Trisomías 13 y 18 asociadas a este mismo factor. El 21,4% indico correctamente la incidencia de Síndrome de Down en niño de mujeres mayores de 35 años. Más del 80% indico correctamente la determinación del Sx. De Down y el Sx. De Turner por cariotipo fetal. Existe desconocimiento sobre la influencia de los defectos congénitos en la mortalidad infantil en nuestro país, así como la incidencia de Síndrome de Down en mujeres mayores de 35 años. El conocimiento de los encuestados resulto aceptable en relación a la etiología y los factores de riesgo y satisfactorio en relación a la prevención de defectos congénitos