Assessment of foodborne pathogens in fresh berries

info:eu-repo/semantics/publishedVersio

Microbiological evaluation of berries and identification of target microorganisms

One of the main challenges in food production is to improve competitiveness by identifying innovations which comply with safety policies and regulations, and guarantee food safety, while at the same time meeting general consumer demands. Consumer expectations are sometimes contradictory. While consumers demand microbiologically safe products with longer shelf-life, they also demand products free from or low in chemical preservatives and of high nutritional and sensory characteristics. The objective of this work, enclosed in the general objective within the framework of the national project Safety Fuit, was to evaluate the microbiological quality of raw materials used in in fruit processing by a Portuguese company. The results obtained will allow this company to set target microorganisms that must be controlled during processing. In this context, several samples of strawberry, blueberry, raspberry and blackberry were anaysed. Microorganisms were detected and/or enumerated and subsequently identified by ISO standard methods and rRNA sequencing. The following parameters were investigated: aerobic mesophilic microorganisms, yeasts and moulds, mesophilic and thermophilic spore forming bacteria, Escherichia coli, Salmonellaspp., Listeria monocytogenes, Bacillus cereus, sulfite-reducing clostridia and Staphylococcus aureus. Results showed that none of the samples were positive forE. coli, L. monocytogenes and S.aureus. However, some positive samples for Salmonellaspp. and sulfite-reducing clostria were observed. Hemolytic B. cereus was also observed, but only three samples (raspberry) presented counts higher than 2 log. Identification of the isolates by rRNA sequencing is ongoing.info:eu-repo/semantics/publishedVersio

Changes in colour and phenolic composition during the early stages of maturation of port in wood, stainless steel and glass

Differences in colour and phenolic composition during the maturation of port in oak wood, stainless steel and glass were examined for a period of 311 days at 18 °C. Principal component analysis (PCA) was used in variable selection, data reduction and data analysis. Nine out of 13 colour and phenolic variables were heavily loaded on PC1 (76.1% of explained variance), and a plot of PC1 scores versus maturation time showed differences in colour and anthocyanins between ports matured in different containers. Ports matured in oak casks developed at a faster rate than the other ports. Total phenolics remained fairly constant in all ports, as monomeric anthocyanins were rapidly depleted during the time of maturation. Polymeric pigments formed during maturation contributed to increases in colour density, hue and the rate of browning. Differences in redox potential between wood matured ports and non-wood matured ports indicated that there were differences in dissolved oxygen which could have affected the maturation rate of these wines

Effect of skin contact and oxygenation of muts on the composition of white port wines

White port wine were made from Malvaela Fina and Rabigata gaps musts that were subjected to different combinations of skin contact and must oxygenation. Increasing skin contact times increased the total phenolics. Total hydroxycinnamoyl tartaric acid, total flavonoids and the formation of brown pigments in the tree-run musts. Both air exposure and hyperoxidation were effective in lowering the concentration of hydroxycinnamoyl tartaric acids and flavonoids it newly fermented wines. Hyperoxidation seemed more effective in removing this phenolic compounds and U1 reducing browning than air expo- sure In wines which had 8 and 25 h of akin contact. Phenolic compounds increased with wood ageing. Although the concentration of hydroxycinnamic acide were lower In all oxygenated wines than in the controls. However must oxygenation prior to fermentation could not prevent further browning of the wines, caused by the production of furans and the increase of flavonoids during that ageing it wood. increasing skin contact generally increased the total monoterpene alcohol concentration for hyperoxidised whesm with some increases it air exposed wines. Total monoterpene alcohol concentration was higher Hyperoxidised than in air exposed wines, made from musts with 8 and 25h of skin contact, after 18 months of wood ageing

Ceramide accumulation mediates inflammation, cell death and infection susceptibility in cystic fibrosis

Microbial lung infections are the major cause of morbidity and mortality in the hereditary metabolic disorder cystic fibrosis, yet the molecular mechanisms leading from the mutation of cystic fibrosis transmembrane conductance regulator (CFTR) to lung infection are still unclear. Here, we show that ceramide age-dependently accumulates in the respiratory tract of uninfected Cftr-deficient mice owing to an alkalinization of intracellular vesicles in Cftr-deficient cells. This change in pH results in an imbalance between acid sphingomyelinase (Asm) cleavage of sphingomyelin to ceramide and acid ceramidase consumption of ceramide, resulting in the higher levels of ceramide. The accumulation of ceramide causes Cftr-deficient mice to suffer from constitutive age-dependent pulmonary inflammation, death of respiratory epithelial cells, deposits of DNA in bronchi and high susceptibility to severe Pseudomonas aeruginosa infections. Partial genetic deficiency of Asm in Cftr(-/-)Smpd1(+/-) mice or pharmacological treatment of Cftr-deficient mice with the Asm blocker amitriptyline normalizes pulmonary ceramide and prevents all pathological findings, including susceptibility to infection. These data suggest inhibition of Asm as a new treatment strategy for cystic fibrosis