Characterization of Salmonella Enteritidis isolated from human samples

This study aimed to characterize Salmonella Enteritidis (SE) isolated from blood (n = 12) and feces (n = 68) of salmonellosis victims in Southern Brazil. All isolates were submitted to antimicrobial susceptibility testing, PCR-ribotyping, and XbaI macrorestriction Pulsed-Field Gel Eletrophoresis (PFGE). Results demonstrated high levels of ampicillin and nalidixic acid resistance, and strains isolated in different geographic regions were clustered together, presenting a common resistance profile. All strains demonstrated similar and related PCR-ribotyping patterns (R1, R2, and R3); being that the predominant profile R1 grouped 47.5% of the strains. PFGE profile P1 grouped the majority of the strains (96.25%), suggesting a clonal relationship among the strains or inability of molecular typing methods to discriminate strains of this serovar. Results suggested on an increase in antimicrobial resistance and that strains of S. Enteritidis with similar PFGE and PCR-ribotyping profiles were involved in several salmonellosis outbreaks in Southern Brazil.     

Characterization of a water-based paint for corrosion protection

Corrosion of steel rebars in reinforced concrete is one of the major problems in the construction industry. Carbonation reactions of concrete with carbon dioxide and, mainly, the chloride salts action are the main causes responsible for concrete degradation. Protective coatings help to improve the durability of concrete structures by acting as a physical barrier against the corrosion agents. Waterborne paints are usually used for concrete protection rather than solvent-based paints since they are less pollutant. The aim of this work is to investigate the influence of the pore size and porosity on the permeability of the paints films toward sodium chloride. Three characterization methods from membrane science were implemented to characterize paint coatings. The time-lag method was used to determine the permeability toward the sodium chloride and toward helium and argon, these for approximately 100% relative humidity. From the seven waterborne paints formulated, only one was found to be suitable for surface protection of reinforced concrete, since its permeability toward NaCl was smaller than 10⁻¹⁴ m² s⁻¹, the threshold value required by National Laboratory of Civil Engineering (LNEC) in Portugal. For the formulated paints, it was observed that the average pore size correlates well with the permeability toward sodium chloride. This is an important result since obtaining the permeability toward sodium chloride of corrosion protective paints is very time consuming, while the average pore size can be obtained in a much shorter time.     

Ethyl group as matrix modifier and inducer of ordered domains in hybrid xerogels synthesised in acidic media using ethyltriethoxysilane (ETEOS) and tetraethoxysilane (TEOS) as precursors

Hybrid silica xerogels favourably combine the properties of organic and inorganic components in one material; consequently these materials are useful for multiple applications. The versatility and mild synthetic conditions provided by the sol-gel process are ideal for the synthesis of hybrid materials. The specific aims of this study were to synthesise hybrid xerogels in acidic media using tetraethoxysilane (TEOS) and ethyltriethoxysilane (ETEOS) as silica precursors, and to assess the role of the ethyl group as a matrix modifier and inducer of ordered domains in xerogels. All xerogels were synthesised at pH 4.5, at 60 °C, with 1:4.75:5.5 TEOS:EtOH:H₂O molar ratio. Gelation time exponentially increased with the ETEOS molar ratio. Incorporation of the ethyl groups into the structure of xerogels reduced cross-linking, increased the average siloxane bond length, and promoted the formation of ordered domains. As a result, a transition from Qⁿ to Tⁿ signals detected in the ²⁹Si NMR spectra, the Si–O structural band in the FTIR spectra shifted to lower wavelength, and a new peak in the XRD pattern at 2θ < 10° appeared in the XRD patterns. Mass spectroscopy detected fragments with high numbers of silicon atoms and a polymeric distribution.     

In vitro intestinal absorption of amino acid mixtures extracted from codfish (Gadus morhua L.) salting wastewater

This study reports on the intestinal permeability of salt‐containing mixtures of amino acids extracted from codfish salting wastewater. Permeability was evaluated in vitro using the Caco‐2 cell line model; cell integrity during exposure to mixtures of amino acids was estimated by measuring the transepithelial electrical resistance (TEER). The effect of salt (NaCl) on the permeability and on the intestinal cell's integrity was also examined. Permeation rate (i.e. transport) was ≥95% for all amino acids except for creatine, for which it was 6%. Values for apparent permeability coefficients, P_app > 10^?5 cm s^?1, for mixture with isotonic concentration of NaCl suggest that amino acids are very likely to be absorbed in humans. Mixture with a hypertonic level of NaCl exerts a cytotoxic effect in intestinal cells resulting in a loss of epithelium integrity. Results show that isotonic mixture of amino acids extracted from codfish salting wastewater could be used in food, feed, cosmetic and pharmaceutical formulations. These applications could contribute to the fish industry sustainability.     

Improvement of mead fermentation by honey‐must supplementation

Through honey's fermentation, diverse beverages can be obtained, among which is mead, an alcoholic drink with 8 to 18% of ethanol (v/v). Since honey is a matrix with a low nutrient concentration and other unfavourable growth conditions, several problems are usually encountered, namely delayed or arrested fermentations, unsatisfactory quality parameters and lack of uniformity of the final product, as well as unpleasant sensory properties. In this context, the aim of this work was to optimize mead production through honey‐must supplementation with (a) salts, (b) vitamins or (c) salts + vitamins. The effects of the honey‐must formulation on the fermentation kinetics, growth profile and physicochemical characteristics of final meads were evaluated. The results showed minor differences in the fermentation profile and time between fermentations with the different formulations. The growth profile was influenced more by the yeast strain than by the supplements added to the honey‐must. In general, the honey‐must composition did not influence meads’ final characteristics, except regarding the SO₂ concentration of the meads produced using the strain QA23. In summary, the addition of salts and/or vitamins to honey‐must had no positive effects on the fermentation, growth profile or characteristics of the final products. Copyright © 2015 The Institute of Brewing & Distilling     

A feasibility study of Lactobacillus plantarum in fruit powders after processing and storage

The aim of this study was to develop fruit powders (apple, banana and strawberry) enriched with a probiotic strain (Lactobacillus plantarum 299v). Two methodologies were proposed: (i) drying of the fruit with probiotic culture incorporated (by convection) or (ii) drying of fruit (by convection) and addition of spray‐dried probiotic culture. In the first methodology, processing caused a notable reduction in probiotic viable counts in apple, but this reduction was lower during drying of banana and strawberry. A large reduction in viable cells was also recorded during storage. In the second methodology, the survival of L. plantarum 299v was considerably higher during spray‐drying, and fruit powders with a microbial content suitable for a probiotic food (10⁸–10⁹ cfu g^?1) were obtained. The fruit powders incorporating L. plantarum 299v can be stored at 4 °C or at room temperature, for at least 3 months. This preliminary study demonstrated that fruit powders are good carriers of probiotic cultures, but the techniques used to produce them should be carefully considered.     

Biochemical characterisation and application of lipases produced by Aspergillus sp. on solid‐state fermentation using three substrates

Lipase from Aspergillus sp. obtained by solid‐state fermentation (SSF) on wheat bran (LWB), soybean bran (LSB) and soybean bran combined with sugarcane bagasse (LSBBC) were 67.5, 58 and 57.3 U of crude lipase per gram substrate, respectively. The optimum pH of activity and stability of the LWB was between 8 and 9, and the optimum temperature of activity and stability was 50 °C and up to 60 °C, respectively. The LSB and LSBBC showed two peaks of optimum pH (4 and 6) and optimal values of temperature and stability at 50 °C. The LSB was stable in the pH range of 6–7, while LSBBC in the range of pH 4–7. All the enzymes show activities on p‐nitrophenyl esters (butyrate, laurate and palmitate). LWB stood out either on the hydrolysis of sunflower oil, presenting 66.1% of the activity over commercial lipase and on the esterification of oleic acid and ethanol, surpassing the activities of the commercial lipases studied. The thin layer chromatography showed that LWB and LSB have produced ethyl esters from corn oil, while LWB produced it from sunflower oil.     

Different ratios of carbon sources in the fermentation of cheese whey and glucose as substrates for hydrogen and ethanol production in continuous reactors

The fermentation of glucose, cheese whey and the mixture of glucose and cheese whey were evaluated in this study from two inocula sources (sludge from a UASB reactor for swine wastewater treatment and poultry slaughterhouse) for hydrogen production in continuous anaerobic fluidized bed reactors (AFBR). For all fermentations, a hydraulic retention time (HRT) of 6 h and a substrate concentration of 5 g COD L⁻¹ were used. In glucose fermentation, the maximum hydrogen yield (HY) was 1.37 mmol H₂ g⁻¹ COD. The co-fermentation of the cheese whey and glucose mixture was favorable for the concomitant production of hydrogen and ethanol, with yields of up to 1.7 mmol H₂ g⁻¹ COD and 3.45 mol EtOH g⁻¹ COD in AFBR2. The utilization of cheese whey as a sole substrate resulted in an HY of 1.9 mmol H₂ g⁻¹ COD. Throughout the study, ethanol fermentation was evident.     

Assessing Rubus honey value: Pollen and phenolic compounds content and antibacterial capacity

Twenty-three honey samples from Galicia (Northwest Spain) were analysed to determine their botanical origin, phenolic compounds and antibacterial activity. In all samples Rubus pollen was predominant, followed by that of Castanea sativa. Other important pollens found belong to Cytisus type, Trifolium repens, Echium, Eucalyptus globulus, Erica umbellata, Erica cinerea, Campanula type and Frangula alnus.Eight phenolic compounds (caffeic, p-coumaric and ellagic acids, pinocembrin, chrysin, galangin, tectochrysin and kaempferol) were determined by solid-phase extraction (SPE) followed by HPLC/DAD analysis. p-Coumaric and ellagic acids were the main constituents of the phenolic fraction (ca. 5.5 mg/kg each, mean value), followed by the pair chrysin plus galangin (ca. 1.2 mg/kg, mean value) and pinocembrin (ca. 1.0 mg/kg, mean value). Antibacterial activity was checked against five Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Enterococcus faecalis and Bacillus cereus) and four Gram-negative bacteria (Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium). B. cereus and P. mirabilis were the most sensitive microorganisms. This is the first study concerning the phenolic compounds and antibacterial activity of Rubus honey, which proved to be a good source of phenolic compounds and antimicrobial agents with potential health benefits.