Effect of microwave oven over the growth and survival of Escherichia coli O157:H7 inoculated in bovine minced meat samples

The use of microwave ovens in food industry is a growing trend. It is used for thawing, drying and cooking food, but the microorganism's inactivation that this treatment may exert or not is still a subject of worldwide discussion. At the same time. Escherichia coli O157:H7 now presents itself as an emerging pathogen, distributed worldwide and associated with food. Its resistance to adverse environments has been widely discussed. The purpose of this work was to determine the effect of different times of exposure and cooking intensities of microwave oven on the survival of this bacterium inoculated into minced meat samples. These were inoculated with a high (10(7)-10(9) CFU/mL) or low (10(7)-10(7) CFU/mL) population of E. coli O157:H7, frozen for 3 days at-4 degrees C and thawed in a Whirlpool microwave oven according to their weight. They were radiated at levels of 70%, 80%, 90% and 100% for periods of 30, 60, 90 and 120 seconds. In each sample the rate of survival of the bacteria was determined according to the methodology described by Vanderzant & Splittstoesser. The results obtained showed that the rate of destruction of the bacteria analyzed was significant (p < 0.005). The number of bacteria present in the meat samples diminished dramatically as the exposure time and temperature increased, even though, for the complete elimination of this microorganism, a prolonged exposure was necessary, even though it did cause undesirable organoleptic characteristics in the food samples.     

Objective and subjective optical-quality measurements in subjects with keratitis and age-related macular degeneration

The use of commercial devices that objectively measure retinal image quality has increased in recent years although limited mostly to the analysis of surgical emmetropization techniques. In this work, we propose the use of optical-quality devices (an aberrometer and a double-pass device) to be extended to other highly prevalent ocular pathologies such as keratitis and age-related macular degeneration. For this, we determined whether the objective data correlate with visual performance. Data, including the contrast-sensitivity function, were taken for 26 patients. The results show a clear correspondence between objective and psychophysical measurements, revealing that optical-quality devices can be useful for additional visual clinical applications.     

Effect of flaxseed oil in diet on fatty acid composition in the liver of Nile tilapia (Oreochromis niloticus)

This study analyzed the effects of different concentrations of flaxseed oil (FO) on the proximate composition and the contents of alpha-linolenic acid (LNA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), and docosahexaenoic (DHA, 22:6n-3) fatty acids in the liver of cultured Nile tilapia (Oreochromis niloticus). During the five-month culture period, tilapias were given diets with incremental concentrations of FO (0.00%; 1.25%; 2.50%; 3.75%, and 5.00%) as a replacement of sunflower oil (control). There was no significant difference in moisture and ash content in the liver between treatments. Protein values ranged from 12.1% (treatment II) to 13.9% (treatment V) and total lipids ranged from 5.6% (treatment V) to 7.2% (treatment II). There was no significant difference between most treatments. Fatty acid methyl esters (FAMEs) were quantitatively analyzed by capillary gas chromatography against a C(23:0), internal standard. Variations in concentrations (in mg g(-1) of total lipids) of fatty acids between treatment I and treatment V ranged from 4.2 to 51.2 (LNA), from 0.2 to 2.3 (EPA), and from 10.6 to 56.2 (DHA), respectively. This experiment demonstrated that increasing amounts of LNA in feed may markedly increase the amounts of LNA, EPA, and DHA in the liver of Nile tilapia.     

Biogeochemistry of metalliferous peats: sulfur speciation and depth distributions of dsrAB genes and Cd, Fe, Mn, S, and Zn in soil cores

Spatial relationships between concentrations of Cd, Fe, Mn, S, and Zn and bacterial genes for dissimilatory sulfate reduction were studied in soils of the Manning peatland region in western New York. Peat cores were collected within a field exhibiting areas of Zn phytotoxicity, and pH and elemental concentrations were determined with depth. The oxidation states of S were estimated using S-XANES spectroscopy. Soil microbial community DNA was extracted from peat soils for ribosomal RNA intergenic spacer analysis (RISA) of diversity profiles with depth. To assess the presence of sulfate-reducing microorganisms (SRM), DNA extracts were also used as templates for PCR detection of dsrAB genes coding for dissimilatory (bi)-sulfite reductase. Elemental distributions, S redox speciation, and detection of dsrAB genes varied with depth and water content. The pH of peat soils increased with depth. The highest concentrations of Zn, Cd, and S occurred at intermediate depths, whereas Mn concentrations were highest in the topmost peat layers. Iron showed a relatively uniform distribution with depth. Concentrations of redox sensitive elements, S and Mn, but not Fe, seemed to respond to variations in water content and indicated vertical redox stratification in peat cores where topmost peats were typically acidic and oxidizing and deeper peats were typically circumneutral and reducing. Even then, S-XANES analyses showed that surface peats contained >50% of the total S in reduced forms while deep peats contained generally <5% of the total S in oxidized forms. While bacterial RISA profiles of the peats were diverse, dsrAB gene detection followed redox stratification chemistry closely. For the most part, dsrAB genes were detected in deeper peats, where S accumulation was evident, while they were not detected in topmost peat layers where Mn accumulation indicated oxic conditions. Combined chemical, spectroscopic, and microbiological analyses indicated that prolonged exposure to dry-wet cycles resulted in the formation of two redox-stratified zones with distinct chemical and microbiological signatures within peat cores of the Manning peatland region. As illustrated in this study, changes in redox conditions affect bacterial community composition and downward mobility of toxic elements, which has implications for water contamination and the design of metal remediation strategies.     

Performance of Cinta Senese pigs and their crosses with Large White 2. Physical, chemical and technological traits of Tuscan dry-cured ham

Technological, chemical and physical traits of cured ham from Cinta Senese and Large White pigs, and their crosses were investigated. Hams were obtained from 29 Cinta Senese (CS), 29 Large White × Cinta Senese (LW × CS) and 12 Large White (LW) pigs, fed a commercial mixture. Sensory and chemical–physical analysis was performed on a sample-slice and on muscles (Biceps femoris – BF; Semimembranosus – SM; Semitendinosus – ST) and subcutaneous fat. CS showed the highest trimming loss and the lowest salting loss. Hams of CS pigs scored higher for fatness than those of LW pigs, LW × CS showing intermediate values. On sample-slice, CS exhibited higher firmness, redness and marbling of lean, and greater fat extension than LW, with crosses having intermediate scores. Muscle moisture was lowest in CS, while both SM and BF from LW had the highest percentage of protein and the lowest of ash. CS showed higher intramuscular fat content than LW × CS and LW. Shear force of BF was higher in CS than in LW × CS and LW. With respect to LW, CS had lower values of L^* in muscles, and higher values of a^* in subcutaneous fat. Subcutaneous fat of CS contained less SFA and more MUFA than LW × CS and LW.     

Compositional and quantitative microtextural characterization of historic paintings by micro-X-ray diffraction and Raman microscopy

This work shows the benefits of characterizing historic paintings via compositional and microtextural data from micro-X-ray diffraction (μ-XRD) combined with molecular information acquired with Raman microscopy (RM) along depth profiles in paint stratigraphies. The novel approach was applied to identify inorganic and organic components from paintings placed at the 14th century Islamic University-Madrasah Yusufiyya-in Granada (Spain), the only Islamic University still standing from the time of Al-Andalus (Islamic Spain). The use of μ-XRD to obtain quantitative microtextural information of crystalline phases provided by two-dimensional diffraction patterns to recognize pigments nature and manufacture, and decay processes in complex paint cross sections, has not been reported yet. A simple Nasrid (14th century) palette made of gypsum, vermilion, and azurite mixed with glue was identified in polychromed stuccos. Here also a Christian intervention was found via the use of smalt, barite, hematite, Brunswick green and gold; oil was the binding media employed. On mural paintings and wood ceilings, more complex palettes dated to the 19th century were found, made of gypsum, anhydrite, barite, dolomite, calcite, lead white, hematite, minium, synthetic ultramarine blue, and black carbon. The identified binders were glue, egg yolk, and oil.     

Ozone-Based Processes Applied to Municipal Secondary Effluents

This study analyzes the performances of 2 methods of oxidation based on ozone, namely ozonation and ozone combined with hydrogen peroxide (O₃/H₂O₂), on two biotreated municipal wastewater effluents. The main parameters monitored to evaluate the effectiveness of the processes were Chemical Oxygen Demand (COD), Dissolved Organic Carbon (DOC) and Biochemical Oxygen Demand (BOD₅). Ozonation and O₃/H₂O₂ treatment removed 44% and 48%, respectively, of the COD, after 90 min, of the secondary effluent of Calafell wastewater treatment plant (Spain). On the secondary effluent from the Grasse wastewater treatment plant (France), these same treatments (O₃; O₃/H₂O₂) achieved, respectively, a degradation of 52% and 100% of the COD after 60 min. The transferred ozone dose (TOD) during Calafell and Grasse effluents' ozonation were 122 mg·L^?1 and 77 mg·L^?1 after 90 min, respectively. A low removal of DOC was monitored during both O₃ or O₃/H₂O₂ treatments applied to Calafell wastewater, respectively 12% and 14%. Better DOC reductions were obtained on the water of Grasse treated with O₃ or O₃/H₂O₂, respectively, 48% and 60%. In addition, ammonia nitrogen was oxidized to nitrate nitrogen thus giving rise to an over ozone consumption. And finally, both processes proceeded with an increase of pH values. These results highlight the strong dependency of O₃ or O₃/H₂O₂ treatment effectiveness in terms of dissolved organic matter (DOM) removal and ozone consumption on wastewater composition (organic and inorganic substances).     

Time-dependence of ferric reducing antioxidant power (FRAP) index in Chilean apples and berries

We hypothesize that the Ferric Reducing Antioxidant Power (FRAP) assay that follows the reaction of Fe(3+)-TPTZ at 593 nm underestimates the antioxidant capacity of fruits, since the standardized time of the reaction (4 min) is not enough to titrate all the reducing compounds available. We measured FRAP, total phenolics and anthocyanins content in a variety of Chilean berry fruits (blueberries, blackberries, raspberries and strawberries) and apples (cv. Fuji, Granny Smith, Pink Lady, Red Delicious and Royal Gala). Taking into account the dependence of FRAP on the time course of the reaction, we propose to measure FRAP indexes after 1 min (FRAP-1), 30 min (FRAP-30) and 120 min (FRAP-120) of incubation. Most fruit extracts showed significant correlations between the antioxidant capacity and the incubation time, although in some cases the FRAP indexes did not correlate with the total phenolics and/or anthocyanins content. In fact, in apples and berries the correlation between anthocyanins content and FRAP indexes decreased with the incubation time. It is concluded that the fruit extracts analyzed require an incubation period higher than the established in the original experimental protocol to reach the equilibrium, due to the presence of a complex mixture of antioxidant compounds. In addition, a kinetic profile should be realized in each sample studied to establish the most suitable incubation period to titrate all the reactive antioxidant species.     

Iron and zinc in vitro potential availability in an infant diet with fortified bread with different iron sources or with the addition of different iron absorption promoters

Home-made diets are the most frequently used complementary foods. In the present work we evaluated iron and zinc availability in a usually consumed infant diet containing either iron-fortified bread with different iron sources: ferrous sulfate, ferrous bisglycinate, NaFeEDTA. We also used non-fortified bread with absorption promoters: ascorbic acid, sodium citrate, Na2EDTA, combined with different beverages. The diet (potato, pumpkin, grits, bread, and apple) was combined with water, milk, tea, a soft drink and an orange-based artificial drink. Mineral dialyzability (D) as an indicator of potential availability was determined using an in vitro method. Statistical analysis was performed by ANOVA, and a posteriori Tukey test. There were no significant differences in FeD between diets with ferrous sulfate or ferrous bisglycinate fortified bread; in NaFeEDTA fortified bread it increased significantly (p<0.05). Iron D increase was greater in diets with bread containing absorption promoters than in those with fortified bread. The orange-based artificial drink increased FeD, while tea and milk decreased it significantly (p < 0.05). Zinc D increased significantly when the bread was fortified either with ferrous sulfate or NaFeEDTA, but remained unchanged in diets with ferrous bisglycinate fortified bread. The addition of tea or milk decreased ZnD while the orange-based artificial drink increased it significantly (p < 0.05). Regarding absorption promoters, the greater values both in FeD and ZnD were observed in diets with iron nonfortified bread containing Na2EDTA.