Bioactive properties of honey with propolis.

Nowadays, propolis is used as an innovative preservative and as a bioactive food supplement. Due to its bitter and astringent flavour, propolis is hardly accepted by consumers. The aim of this study was to obtain a likeable food product made with honey and propolis, whose antimicrobial, antioxidant and anti-inflammatory properties were enhanced in comparison with those of the base honeys used. 0.1%, 0.3% and 0.5% soft propolis extracts were added to honeys and the products that most appealed to the users were subjected to further research. Total phenolics, flavonoids, ABTS free radical and hydroxyl radicals scavenging and anti-inflammatory activities increased in all mixtures. Antimicrobial activity of the combined products showed synergic effects, resulting in higher results than those of the base honeys and propolis extracts. Therefore, honeys enriched with small amounts of propolis extracts are promising functional foods.

Microbiological counts during beet sugar extraction.

In order to discover the main microbial populations present throughout the process of beet sugar extraction and to identify the steps where possible control measures could be implemented, four Spanish beet sugar extraction factories were investigated. Eighteen stages were sampled at each factory and analyzed for several microbial groups and physicochemical parameters. Beets, cossettes, and diffusion juices were the most contaminated samples during beet sugar extraction, and mesophiles, thermophiles, and yeasts were the most numerous microbiota. Differences in contamination among factories and among stages of the sugar extraction process were statistically significant (P < 0.01). Beets and cossettes showed high numbers of mesophiles and lactic acid bacteria, with gum-forming bacteria and yeasts being at levels of >6 log CFU/g. Diffusion juices were highly contaminated with aerobic mesophiles, lactic acid bacteria, and thermophiles. Beet-washing water, equipment, and air were also important sources of contamination; in contrast, diffusion water showed moderate levels of microorganisms due to the acid treatment performed. Gum-forming bacteria, which are present at high levels from the first step of the extraction, survive the diffusion process and remain in the diffusion juice, where they may produce "gums" responsible for obstruction of filters. Thermophiles were present, although at levels lower than expected in most samples. Other microbial groups, particularly yeasts, may also contribute to the destruction of sugar. No biocides were used during the beet sugar extraction in the factories investigated.

Composición físico-química del queso colonial (Brasil) / Physical and chemical composition of colonial cheese (Brasil)

Se ha llevado a cabo una evaluación físico-química del queso tipo Colonial, una variedad de queso elaborado a partir de leche cruda de vaca, de corta o ninguna maduración y que no se encuentra bajo normalización del Ministerio de Agricultura de Brasil. Fueron estudiadas cien (100) muestras del queso tipo Colonial, elaborado con leche cruda de vaca recogidas en zonas turísticas del Sur de Brasil. Los parámetros estudiados han sido: determinación de proteína, grasa, humedad/extracto seco, cenizas, cloruros, pH y actividad de água (Aw). (AU)

The physical and chemical composition of Colonial raw cow‘s milk cheese produced in Rio Grande do Sul ( South Brasil) were studied. Hundred samples of this soft and manufacturated cheese were collected in the two main touristic areas in South Brasil. The physical and chemical characteristics studied were: protein and fat content, humidity/ dry extract, salt concentration, pH and water activity (Aw) (AU)

Surface mycoflora of a Spanish fermented meat sausage and toxigenicity of Penicillium isolates.

The surface mycoflora of "chorizo de Cantimpalos", a Spanish variety of fermented meat sausage characterised by a natural white covering, has been investigated. Among 54 mould strains isolated, 38 belonged to Penicillium subgenus Penicillium. The major species found (18 isolates) was identified as Penicillium commune, and the other dominant species (13 isolates) was identified as P. olsonii. None of the P. olsonii isolates produced cyclopiazonic acid, mycophenolic acid, roquefortine C. patulin or ochratoxin A, but all P. commune isolates produced cyclopiazonic acid. Toxicity to Artemia salina larvae was very high for all P. commune isolates investigated, while no isolates of P. olsonii studied were toxic to these crustaceans. The results may assist in selection of nontoxic strains, which could be used as surface starters in the manufacture of this type of sausage. The apparent inability to produce penicillin is a valuable characteristic to take into account in the selection process.

Yeast populations on Spanish fermented sausages.

Yeast populations on 24 lots of Spanish fermented sausages, made by four factories (F1, F2 and F4, artisanal; F3, industrial) were investigated throughout manufacture and the influence of different variables evaluated. In addition, 41 yeast strains were identified at the species level using two miniaturised systems: ATB32C (API System) and Vitek Yeast Biochemical Card (Vitek YBC). Levels of yeasts found in the sausage mixture (mean counts around 4 log units/g) were similar to those described by other authors. In sausages from factories F1 and F2, a further increase was noted, reaching 5.5 log units/g after fermentation. Counts subsequently decreased to 3.6 and 5 log units/g, respectively. In sausages from factories F3 and F4, decreasing counts were observed from the beginning, particularly in sausages from F3, where yeasts were almost absent in the finished product. Type of manufacture and sausage diameter, were the variables most influencing yeast counts. Debaryomyces hansenii (teleomorph of C. famata) was the dominant species, being found at all stages of manufacture. Trichosporon ovoides (formerly T. beigelii), Yarrowia lipolytica (perfect form of C. lipolytica), C. intermedia/curvata, C. parapsilosis, C. zeylanoides and Citeromyces matritensis (teleomorph of C. globosa) were also present. Direct identification was possible only with 50% of the total of strains investigated, although a higher number of strains was identified using the API than the Vitek YBC system.

Bacterial microflora of wild brown trout (Salmo trutta), wild pike (Esox lucius), and aquacultured rainbow trout (Oncorhynchus mykiss).

Initial numbers of bacteria associated with wild (brown trout and pike) and cultured (rainbow trout) freshwater fish as well as with the water in which they were caught were determined. Subsequently, a total of 979 randomly selected isolates were characterized and identified to the genus level. For all counts performed (aerobes, psychrotrophs, anaerobes, Enterobacteriaceae, and enterococci), no significant differences were observed in water samples, the highest level corresponding to psychrotrophs in pike environments (4.23 X 10(3) CFU/ml). Overall, the skin and intestinal content of brown trout were the most contaminated, while rainbow trout specimens (gills and gut) yielded the lowest numbers. For all bacterial groups, pike gills had the highest numbers. Counts for all of the sampling sites compare well with findings in other temperate geographical environments. Biological characteristics (feeding and skin properties) and the use of antimicrobials in aquaculture might have influenced these results. Motile and nonmotile aerobic gram-negative bacteria together with Enterobacteriaceae accounted for 50 to 70% of the psychrotrophs isolated from water. Micrococcaceae, lactic acid bacteria, Bacillus, and coryneforms were also found. The groups represented in psychrotrophic isolates from the outer surfaces do not reflected those detected in water, so it was common that those organisms recovered in significant numbers from fish were not detected in surrounding habitat of the fish. Motile aeromonads and Carnobacterium were the dominant psychrotrophs in the guts of pike and brown trout, respectively. The intestinal content of reared fish gave a high incidence of Bacillus and coryneforms, while Enterobacteriaceae was absent. Again, rearing practices could have influenced this finding. Listeria monocytogenes was not detected in any of the examined samples. Two strains of Salmonella, which belonged to the same serovar and lysotype, were recovered from pond-water samples taken from one facility on different sampling days. From the gut of a pike specimen and from the pike's environment, two Plesiomonas shigelloides strains of different serovars were recovered. These latter four strains were resistant to a considerable number of antimicrobial compounds (multiple antibiotic resistance indices > 0.2).

Production of patulin and cytochalasin E by Aspergillus clavatus during malting of barley and wheat.

Production of patulin and cytochalasin E by four strains of Aspergillus clavatus during small-scale laboratory malting of barley at 16 and 25 degrees C was investigated. Fungal biomass, measured as ergosterol, appeared to be greater at 25 than at 16 degrees C, but marked differences were observed between the degree of colonization by the different strains. Patulin was detected in extracts by HPLC. Net production was greater at 16 degrees C, but amounts were strain dependent. Except for one strain, cytochalasin E was detected only in barley malted at 25 degrees C. In experiments with wheat inoculated with two A. clavatus strains, ergosterol levels in the green malts were generally greater than in corresponding barley malts. Patulin was again detected in all samples, with the equivalent of 22.4 mg/kg being detected in one sample at 16 degrees C, but cytochalasin E was only found at 25 degrees C, the highest level detected being 13.8 mg/kg. In samples of barley spiked with toxin and kilned at 80 degrees C for 24 h, only about one-fifth of the amount of toxin recovered from corresponding unkilned controls was detected. It is indicated that differences in both contaminant strains and temperature in different maltings may account for disparities between symptoms reported for individual outbreaks of mycotoxicosis associated with malting by-products.

Characterization and extracellular activity of psychrotrophic bacteria isolated from Villalón cheese (fresh variety of Spanish sheep's milk cheese).

The incidence of psychrotrophic bacteria was investigated in a Spanish fresh ewes' cheese (Villalón). Counts of mesophiles and psychrotrophs were (log cfu/g) 5.72 +/- 1.10 and 3.90 +/- 1.01, respectively, for factory cheeses made from pasteurized-milk. Figures for hand-made cheeses made from raw-milk were 7.35 +/- 0.48 and 6.94 +/- 0.65, respectively. A total of 59 representative psychrotrophic isolates were characterized and tested for protease and lipase production at 7 and 30 degrees C. The strains were assigned to Enterobacteriaceae (predominant in raw-milk cheese), heterofermentative lactic acid bacteria (dominant in pasteurized-milk cheese and absent in raw-milk cheese) and Pseudomonas. More than 73% of the Enterobacteriaceae produced both proteolytic and lipolytic enzymes at either 30 or 7 degrees C. This percentage is considerably higher than those previously reported. The seven isolates of pseudomonads investigated produced proteases at 7 degrees C and six were positive at 30 degrees C; lipolytic activity was shown by five of the isolates at both temperatures. Among the heterofermentative lactic acid bacteria seven of the ten isolates were proteolytic at 30 degrees C.

Mycotoxins in two Spanish cheese varieties.

Samples of cheeses naturally contaminated with moulds (12 samples of mouldy Manchego cheese and 10 of a naturally ripened blue cheese) were analysed for the presence of mycotoxins (aflatoxins BI and MI, sterigmatocystin, patulin, penicillic acid and mycophenolic acid in Manchego cheese, and mycophenolic acid and roquefortine in blue cheese). In addition, 24 Penicillium and Aspergillus strains isolated from the samples were assessed for their mycotoxigenicity. Four of Manchego cheese samples were positive to mycophenolic acid and one sample of blue cheese contained roquefortine. The rest of mycotoxins investigated were not found. One Aspergillus strain isolated from Manchego cheese showed the ability to produce aflatoxin MI. The rest of strains from these samples being no producers. In contrast, 7 out of 9 Penicillium (P. roqueforti) strains isolated from blue cheese were able to produce roquefortine, with one strain also producing mycophenolic acid.