Home About us Contact
|
Home About us Contact | ||
|
|
||
Log CFU/g (log + g)
Selected AbstractsINDICATOR AND PATHOGENIC BACTERIA IN GUACAMOLE AND THEIR BEHAVIOR IN AVOCADO PULPJOURNAL OF FOOD SAFETY, Issue 4 2001SOFÍ M. ARVIZU-MEDRANO ABSTRACT The presence of some indicator microorganisms and pathogenic bacteria in guacamole sampled from restaurants and street vendors, and the behavior of Salmonella spp., Staphylococcus aureus, and Escherichia coli O157:H7 were studied in avocado pulp. Coliform, yeast and mold populations showed a wide dispersion, in agreement with the diversity of sanitary conditions observed among places sampled. The frequency of Salmonella spp., Listeria monocytogenes, and E. coli were 1.3, 16.0, and 60.0 %, respectively; with higher numbers among street vendors. Populations of E. coli ranged from 29 to 3800 NMP/g and S. aureus from 2.95 to 5.35 log CFU/g. Thirteen out of 16 hemolytic L. monocytogenes strains were pathogenic for mice. In avocado pulp Salmonella spp. and E. coli O157:H7 showed a lag phase close to 3 h, and a generation time of 54 min and 1.23 h, respectively. No growth of pathogens was observed in avocado pulp stored at 4-7C. [source] Antilisterial Activity and Consumer Acceptance of Irradiated Chicken Breast Meat Vacuum-Infused with Grape Seed and Green Tea Extracts and Tartaric AcidJOURNAL OF FOOD SCIENCE, Issue 7 2010K.F. Over Abstract:, Contamination of poultry with pathogenic bacteria contributes to human foodborne disease, causes damage to industry brand names, and has a significant economic impact on the food industry in the form of both damage to industry brand names and losses associated with recalls. Irradiation is a safe and effective means of decontaminating poultry products, but the maximum dose strengths allowed negatively impact poultry sensory quality characteristics. The 1st objective of this study was to investigate the potential interactive inhibitory effects of natural antimicrobials as components of a vacuum-marination in addition to various dose levels of irradiation. Tartaric acid (TA) at 2 levels and grape seed (GS) and green tea (GT) extracts were combined, vacuum-infused into chicken breast fillets, and irradiated at 1, 2, and 3 kGy by electron beam irradiation. The 2nd objective was to use a consumer test group to evaluate TA and plant extract infusion into chicken breast fillets with and without irradiation at 2 kGy on overall impression, flavor, texture, appearance, and tenderness. The results showed that samples vacuum-infused with TA at 37.5 and 75.0 mM and irradiated at 1 kGy significantly reduced Listeria monocytogenes (L.m.) levels by 2 and 3 log CFU/g compared to the control after 12 d of refrigerated storage. Vacuum-infusion of TA at 37.5 and 75.0 mM at 2 and 3 kGy irradiation, reduced L.m. to near nondetectable levels. The addition of TA and GS and GT to chicken breast fillets with and without irradiation did not significantly impact consumer preference, tenderness, appearance, or flavor. The addition of tartaric acid and natural plant extracts to chicken marinades could contribute to the prevention of L.m. contamination. [source] Whole-Leaf Wash Improves Chlorine Efficacy for Microbial Reduction and Prevents Pathogen Cross-Contamination during Fresh-Cut Lettuce ProcessingJOURNAL OF FOOD SCIENCE, Issue 5 2010Xiangwu Nou Abstract:, Currently, most fresh-cut processing facilities in the United States use chlorinated water or other sanitizer solutions for microbial reduction after lettuce is cut. Freshly cut lettuce releases significant amounts of organic matter that negatively impacts the effectiveness of chlorine or other sanitizers for microbial reduction. The objective of this study is to evaluate whether a sanitizer wash before cutting improves microbial reduction efficacy compared to a traditional postcutting sanitizer wash. Romaine lettuce leaves were quantitatively inoculated with,E. coli,O157:H7 strains and washed in chlorinated water before or after cutting, and,E. coli,O157:H7 cells that survived the washing process were enumerated to determine the effectiveness of microbial reduction for the 2 cutting and washing sequences. Whole-leaf washing in chlorinated water improved pathogen reduction by approximately 1 log unit over traditional cut-leaf sanitization. Similar improvement in the reduction of background microflora was also observed. Inoculated "Lollo Rossa" red lettuce leaves were mixed with noninoculated Green-Leaf lettuce leaves to evaluate pathogen cross-contamination during processing. High level (96.7% subsamples, average MPN 0.6 log CFU/g) of cross-contamination of noninoculated green leaves by inoculated red leaves was observed when mixed lettuce leaves were cut prior to washing in chlorinated water. In contrast, cross-contamination of noninoculated green leaves was significantly reduced (3.3% of subsamples, average MPN ,,0.3 log CFU/g) when the mixed leaves were washed in chlorinated water before cutting. This result suggests that whole-leaf sanitizing washes could be a practical strategy for enhancing the efficacy of chlorine washes for pathogen reduction and cross-contamination prevention. Practical Application:, Freshly cut leafy greens release large amount of organic matter that negatively impact the chlorine washing efficacy. Implementing the primary antimicrobial intervention step of chlorine washing prior to cutting can significantly improve the efficacy of microbial reduction and minimize pathogen cross-contamination. [source] Active Packaging of Fresh Chicken Breast, with Allyl Isothiocyanate (AITC) in Combination with Modified Atmosphere Packaging (MAP) to Control the Growth of PathogensJOURNAL OF FOOD SCIENCE, Issue 2 2010Joongmin Shin ABSTRACT:,Listeria monocytogenes,and,Salmonella typhimurium,are major bacterial pathogens associated with poultry products. Ally isothiocyanate (AITC), a natural antimicrobial compound, is reportedly effective against these pathogenic organisms. A device was designed for the controlled release of AITC with modified atmosphere packaging (MAP), and then evaluated for its ability to control the growth of,L. monocytogenes,and,S. typhimurium,on raw chicken breast during refrigerated storage. In order to obtain controlled release during the test period, a glass vial was filled with AITC and triglyceride. It was then sealed using high-density polyethylene film. The release of AITC was controlled by the concentration (mole fraction) of AITC in the triglyceride and by the AITC vapor permeability through the film. The fresh chicken samples were inoculated with one or the other of the pathogens at 104 CFU/g, and the packages (with and without AITC-controlled release device) were flushed with ambient air or 30% CO2/70% N2 before sealing, and then stored at 4 °C for up to 21 d. The maximum reduction in MAP plus AITC (compared to MAP alone) was 0.77 log CFU/g for,L.,monocytogenes,and 1.3 log CFU/g for,S.,typhimurium. The color of the chicken breast meat was affected by the concentration of AITC. Overall, a release rate of 0.6 ,g/h of AITC was found to not affect the color, whereas at 1.2 ,g/h of AITC the surface of the chicken was discolored. [source] Physical Properties of Gelidium corneum,Gelatin Blend Films Containing Grapefruit Seed Extract or Green Tea Extract and Its Application in the Packaging of Pork LoinsJOURNAL OF FOOD SCIENCE, Issue 1 2009Y.-H. Hong ABSTRACT:, Edible Gelidium corneum,gelatin (GCG) blend films containing grapefruit seed extract (GFSE) or green tea extract (GTE) were manufactured, and the quality of pork loins packed with the film during storage was determined. Tensile strength (TS) and water vapor permeability (WVP) of the films containing GFSE or GTE were better than those of the control. The film's antimicrobial activity against Escherichia coli O157:H7 and Listeria monocytogenes increased with increasing antimicrobial concentration, resulting in a decrease in the populations of bacteria by 0.77 to 2.08 and 0.91 to 3.30 log CFU/g, respectively. Pork loin samples were inoculated with E. coli O157:H7 and L. monocytogenes. The samples packed with the GCG film containing GFSE (0.08%) or GTE (2.80%) had a decrease in the populations of E. coli O157:H7 and L. monocytogenes of 0.69 to 1.11 and 1.05 to 1.14 log CFU/g, respectively, compared to the control after 4 d of storage. The results showed that the quality of pork loins during storage could be improved by packaging them with the GCG film containing GFSE or GTE. [source] Inactivation of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes on Stored Iceberg Lettuce by Aqueous Chlorine Dioxide TreatmentJOURNAL OF FOOD SCIENCE, Issue 9 2008Yun-Jung Kim ABSTRACT:, Inactivation of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes in iceberg lettuce by aqueous chlorine dioxide (ClO2) treatment was evaluated. Iceberg lettuce samples were inoculated with approximately 7 log CFU/g of E. coli O157:H7, S. typhimurium, and L. monocytogenes. Iceberg lettuce samples were then treated with 0, 5, 10, or 50 ppm ClO2 solution and stored at 4 °C. Aqueous ClO2 treatment significantly decreased the populations of pathogenic bacteria on shredded lettuce (P < 0.05). In particular, 50 ppm ClO2 treatment reduced E. coli O157:H7, S. typhimurium, and L. monocytogenes by 1.44, 1.95, and 1.20 log CFU/g, respectively. The D10 -values of E. coli O157:H7, S. typhimurium, and L. monocytogenes in shredded lettuce were 11, 26, and 42 ppm, respectively. The effect of aqueous ClO2 treatment on the growth of pathogenic bacteria during storage was evaluated, and a decrease in the population size of these pathogenic bacteria was observed. Additionally, aqueous ClO2 treatment did not affect the color of lettuce during storage. These results suggest that aqueous ClO2 treatment can be used to improve the microbial safety of shredded lettuce during storage. [source] Effectiveness of Radiation Processing for Elimination of Salmonella Typhimurium from Minimally Processed Pineapple (Ananas comosus Merr.)JOURNAL OF FOOD SCIENCE, Issue 3 2007Ravindranath Shashidhar ABSTRACT:, The microbiological quality of market samples of minimally processed (MP) pineapple was examined. The effectiveness of radiation treatment in eliminating Salmonella Typhimurium from laboratory inoculated ready-to-eat pineapple slices was also studied. Microbiological quality of minimally processed pineapple samples from Mumbai market was poor; 8.8% of the samples were positive for Salmonella. D10 (the radiation dose required to reduce bacterial population by 90%) value for S. Typhimurium inoculated in pineapple was 0.242 kGy. Inoculated pack studies in minimally processed pineapple showed that the treatment with a 2-kGy dose of gamma radiation could eliminate 5 log CFU/g of S. Typhimurium. The pathogen was not detected from radiation-processed samples up to 12 d during storage at 4 and 10 °C. The processing of market samples with 1 and 2 kGy was effective in improving the microbiological quality of these products. [source] Ultrasonication and Fresh Produce (Cos lettuce) PreservationJOURNAL OF FOOD SCIENCE, Issue 2 2006Said Ajlouni ABSTRACT Washing Cos lettuce in various sanitizers at different concentrations with and without ultrasonication (40 KHz) reduced the microbiological counts by 1 to 2.5 log colony-forming units (CFU)/g immediately after washing. Ultrasonication of Cos lettuce in water, chlorinated water, peracetic acid, hydrogen peroxide, and their combinations at various temperatures (4 °C, 20 °C, 35 °C, 47 °C, and 50 °C) had no significant effects (P > 0.05) on the total or the psychrophilic counts during storage at 10 °C. The total count in Cos lettuce reached 9.74 ± 0.035 log CFU/g after ultrasonication (2 min at 50 °C) in chlorinated water (100 mg/L) and storage for 6 d at 10 °C. Extending the ultrasonication (40 kHz) of Cos lettuce for up to 20 min did not improve the bactericidal effect of ultrasonication. However, long-time ultrasonication (20 min) caused significant (P < 0.05) damage to the quality of Cos lettuce tissues. [source] Hydrogen Peroxide and Calcium Chloride Added to Irrigation Water as a Strategy to Reduce Bacterial Populations and Improve Quality of Fresh MushroomsJOURNAL OF FOOD SCIENCE, Issue 6 2005Naveen Chikthimmah ABSTRACT The quality and value of fresh mushrooms are often diminished by the presence of high bacterial populations that cause a brown, blotchy appearance. The objective of the present research was to evaluate the addition of hydrogen peroxide and/or calcium chloride to irrigation water as a means to reduce total bacterial populations on fresh mushrooms. Crops were grown using commercial mushroom growing practices except for the addition of 0.75% hydrogen peroxide and/or 0.3% calcium chloride irrigation water added to the crop starting 11 d after the casing layer was applied on top of mushroom compost. Irrigation water without the added treatments acted as the control. Mushrooms were aseptically sampled from the production beds for enumerating bacterial counts. Total aerobic bacterial populations were determined by standard microbiological plating procedures. Mushroom whiteness (L -value) and color (delta E) after harvest and postharvest storage were measured using a Minolta chromameter. Harvested mushrooms were separated by treatment and weighed to record yield. Mushrooms irrigated with water (control) had 7.3 log colony-forming units (CFU) of aerobic bacterial populations per gram of fresh mushroom tissue. Compared with the control, irrigation with 0.75% hydrogen peroxide and 0.3% calcium chloride reduced the bacterial populations on fresh mushrooms by 87% (6.4 log CFU/g). Irrigation with hydrogen peroxide and calcium chloride significantly enhanced mushroom whiteness after harvest as well as after 6 d of postharvest storage at 12 °C. The irrigation treatments did not have a significant effect on crop yields; hence, the addition of hydrogen peroxide and calcium chloride to irrigation water was demonstrated to have good potential as a practical strategy to reduce bacterial populations and to improve the quality of fresh mushrooms. [source] Chemical, Microbiological, and Sensory Quality of Cod Products Salted in Different BrinesJOURNAL OF FOOD SCIENCE, Issue 1 2005Maria J. Rodrigues ABSTRACT: Studies were carried out on the effect of different brines containing high concentrations of calcium chloride (CaCl2, 0.8%w/w), magnesium chloride (MgCl2, 0.4%w/w), and potassium chloride (KCl, 50%) on the chemical (chloride and moisture contents), microbial (total viable counts, total coliforms, enterococci, and staphylococci), and sensory quality of salted cod. The brines were prepared from combinations of the Ca, Mg, and K ions and sodium chloride (NaCl) at pH 6.5 and 8.5. Additionally, 3 salts (one composed solely of NaCl, another commercial sea salt from the southern Europe and, finally, a natural salt from northern Europe) were also tested. Principal component analysis structured the chemical and microbiology data in 3 clusters: (1) an extreme cluster, formed by cod brined in the commercial sea salt, which achieved the highest microbiological counts, namely 4.1 log CFU/g on plate count agar (PCA) and 1250 coliforms/g; (2) an intermediate cluster composed of cod salted in brine containing 50% NaCl, 0.4% MgCl2, and 49.6% KCl (pH 6.5); and (3) a central cluster, including all the other treatments, which presented the lowest microbiological counts, namely 2.4 log CFU/g on PCA and 20 coliforms/g. Although the batches of the intermediate cluster presented slightly higher total viable and staphylococci counts than the central cluster, the presence of Mg and K ions improved the color of the salted product. In the assayed concentrations, CaCl2, MgCl2, and KCl can be used in the brining of cod without adversely affecting the microbiological and sensory quality of the salted cod. [source] Characterization of ammonia-assimilating bacteria in a lagoon for wastewater from a paddock of dairy cattleANIMAL SCIENCE JOURNAL, Issue 1 2002Hiraku SASAKI ABSTRACT We investigated microorganisms that assimilated ammonia in lagoon treatment processes. Ammonia-assimilating microorganisms were detected by nitrogen-limited medium that contained ammonia as the sole nitrogen source. Numbers of ammonia-assimilating aerobes (log CFU/g) were 3.4, 4.8, 5.0, 4.8 and 5.0 (log CFU/mL) on the culture plate incubated at 4°C, 10°C, 15°C, 20°C and 25°C, respectively. Many isolates used ammonia in high rates when they were purely cultivated in nitrogen-limited medium added to sterilized lagoon extract. Many of them used ammonia even when they were cultivated in media containing viable microbial flora of the lagoon. Among them, enterobacteriaceae and Pseudomonas sp. were identified by analysis of 16S ribosomal DNA. [source] Acrylic polymers as thickening agents for tetraglycol cosolventJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2006Giulia Bonacucina Abstract This article evaluated the thickening properties of two different Eudragits, L and RS, in tetraglycol cosolvent in order to obtain high viscosity systems characterized by controlled release properties. Tetraglycol was chosen for its ability to dissolve a wide range of water insoluble drugs, while Eudragit RS and L for their specific dissolution and permeability properties under physiological conditions. Study of the rheological properties was performed to characterize elastic and viscous properties of Eudragit/tetraglycol samples in function of frequency and temperature. For all systems, the results outlined a liquid like behavior, as observed for dilute polymer solutions. In fact the fitting of the log G,-log G,, versus frequency curves showed a good agreement with the Rouse or Zimm models. So despite the increase in viscosity, samples still behaved like liquid systems. After the addition of paracetamol the release characteristics were defined pointing out the great release control properties of both Eudragit L and RS, which showed different release kinetics depending on the pH of the environment. Semisolid Eudragits/tetraglycol systems can be considered as a new alterative for the sustained release of insoluble or poorly water-soluble drugs. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95:726,736, 2006 [source] Influence of side-chain structures on the viscoelasticity and elongation viscosity of polyethylene meltsPOLYMER ENGINEERING & SCIENCE, Issue 11 2002Gwo-Geng Lin Metallocene-catalyzed, low-density and linear low-density polyethylenes with similar melt indexes were used to investigate how side-chain structures influence the elongation viscosity and viscoelastic properties. The viscoelastic properties were determined with a rotation rheometer, while the elongation viscosities were acquired by using isothermal fiber spinning. The Phan-Thien-Tanner (PTT) model was also used to understand how the side-chain structure affects the elongation behavior. Experimental results demonstrate that the log G, vs. log G, plot can qualitatively describe the effects of the side chain branch on the rheological properties of polyethylene melts. According to the results determined by the PTT model, low-density polyethylene (LDPE) has low elongation viscosities at high strain rates. This low elongation viscosity can be attributed to the fact that LDPE has high shear thinning behavior. The long-chain branching tends to increase entanglements, thereby enhancing the storage modulus, elongation viscosity and shear-thinning behaviors. Uniform side-chain distribution lowers the entanglements, which results in a low storage modulus, elongation viscosity and shear-thinning behavior. [source] Occurrence of coagulase-positive Staphylococci, microbial indicators and physical,chemical characteristics of traditional semihard cheese produced in BrazilINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 3 2009FABIANA R. VIANA Coagulase-positive Staphylococci and microbial indicators of the ,Requeijão do Norte', a traditional semihard cheese, were surveyed in Brazil. Coagulase-positive Staphylococci were found in quantities of up to 9.4 log cfu/g. The coagulase gene was detected in isolates physiologically classified as coagulase-negative. The SEB and TSST-1 toxins were detected. Salmonella spp. were not detected. High levels of total and fecal coliforms (, 210 MPN/g) and moulds (, 6.48 log cfu/g) were found in most samples. The values of physical,chemical parameters and water activity showed the greatest variations. These results suggest a possible risk that this cheese may pose to consumers. [source] THE EFFECT OF PRETREATMENT OF SHREDDED CELERIAC USING SOLUTIONS OF ENZYMATIC BROWNING INHIBITORS ON THE QUALITY OF MINIMALLY PROCESSED PRODUCTJOURNAL OF FOOD QUALITY, Issue 5 2007BIETA, RADZIEJEWSKA-KUBZDELA EL ABSTRACT The study investigated the effect of soaking celeriac flakes in solutions containing various concentrations of enzymatic browning inhibitors on the quality of stored minimally processed product. Ascorbic acid (0.2,0.5%), 4-hexylresorcinol (0.003,0.01%), sodium chloride (0.1,0.5%) and sodium lactate (2,3%) were used as browning inhibitors. On the basis of the conducted tests, it was found that among the applied browning inhibitors, only ascorbic acid had an advantageous effect on the quality of stored celeriac flakes. Along with an increase in its concentration in the solution (0.2,0.5%) used for the pretreatment of the flakes, the value of color parameter a* decreased, while the value of parameter b* increased. At the concentration of ascorbic acid in the solution exceeding 0.25%, flake color in the sensory examination was evaluated as desirable. An increase of ascorbic acid concentration in the solution in the range from 0.2 to 0.4% resulted in a decrease in the total mesophilic and psychrophilic bacteria counts, respectively, by 3 and 1 log cfu/g of the stored product. PRACTICAL APPLICATIONS Minimal processing of celeriac provides convenience for consumers and many economic benefits for producers. Minimal processing of celeriac can induce disadvantageous changes in tissue, which may lead to darkening of the flakes and deterioration of product sensory attributes. Moreover, shredded raw material constitutes an excellent medium for the development of microorganisms. This article contains information about the effectiveness of enzymatic browning inhibitors for extending the shelf life of celeriac flakes. We show a range of concentrations of inhibitors, which improve the preservation of color, intrinsic taste and microbial quality of minimally processed celeriac. [source] EFFECT OF STORAGE TEMPERATURE ON THE GROWTH OF LISTERIA MONOCYTOGENES ON QUESO BLANCO SLICES,JOURNAL OF FOOD SAFETY, Issue 3 2006GAYLEN A. UHLICH ABSTRACT A five-strain cocktail of Listeria monocytogenes (104 cfu/mL) was inoculated onto individual vacuum-packaged slices (ca. 50 g each) of a commercial, Hispanic-style cheese, that being Queso Blanco. Growth was determined at appropriate intervals during storage at 5, 10, 15, 20 and 25C. In general, as the incubation temperature increased, a shorter lag phase duration (LPD) and a faster growth rate (GR) were observed. The LPD values at 5, 10, 15, 20 and 25C were 65.3, 19.9, 2.1, 8.4 and 11.4 h, respectively. The GR values were 0.011, 0.036, 0.061, 0.090 and 0.099 log cfu/h at 5, 10, 15, 20 and 25C, respectively. There were no statistical differences in LPD at 10, 15, 20 and 25C. However, the LPD during growth at 5C was statistically (P , 0.05) longer than at all other temperatures. The GR values at 20 and 25C were not significantly different from each other, whereas the GR values at 5, 10 and 15C were significantly different from each other as well as from the GR at 20 and 25C (P , 0.05). The maximum population density (MPD) showed relatively little variation over the range of storage temperatures tested, with an average of 8.38 log cfu/g (SD = 0.33). The results of this study indicate that not even the lowest trial temperature of 5C prevented growth over time of the inoculated L. monocytogenes on this sliced product, and that proper storage and handling procedures are required to prevent the bacterium from contaminating the product and/or to control its growth. [source] HD 209621: abundances of neutron-capture elements,MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2010Aruna Goswami ABSTRACT High-resolution spectra obtained from the Subaru Telescope High Dispersion Spectrograph have been used to update the stellar atmospheric parameters and metallicity of the star HD 209621. We have derived a metallicity of [Fe/H]=,1.93 for this star, and have found a large enhancement of carbon and of heavy elements, with respect to iron. Updates on the elemental abundances of four s-process elements (Y, Ce, Pr, Nd) along with the first estimates of abundances for a number of other heavy elements (Sr, Zr, Ba, La, Sm, Eu, Er, Pb) are reported. The stellar atmospheric parameters, the effective temperature, Teff, and the surface gravity, log g (4500 K, 2.0), are determined from local thermodynamic equilibrium analysis using model atmospheres. Estimated [Ba/Eu]=+0.35, places the star in the group of CEMP-(r+s) stars; however, the s-elements abundance pattern seen in HD 209621 is characteristic of CH stars; notably, the second-peak s-process elements are more enhanced than the first-peak s-process elements. HD 209621 is also found to show a large enhancement of the third-peak s-process element lead (Pb) with [Pb/Fe]=+1.88. The relative contributions of the two neutron-capture processes, r and s, to the observed abundances are examined using a parametric model-based analysis, which hints that the neutron-capture elements in HD 209621 primarily originate in s-process. [source] Spectroscopic and photometric observations of the selected Algol-type binaries , II.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008V2080 Cygni, V2365 Ophiuchi ABSTRACT This paper is the second in the planned series of investigations. We present new radial velocities and photometric observations of V2080 Cyg and V2365 Oph. New UBV photometric data and radial velocities were analysed for the systems' parameters. While V2080 Cyg consists of two nearly equal F-type main-sequence stars, V2365 Oph has two different components, namely an early A-type primary and a G-type secondary star. New ephemerides are calculated for both systems. The masses of the component stars have been derived as 1.19 ± 0.02 and 1.16 ± 0.02 M, for V2080 Cyg and 1.97 ± 0.02 and 1.06 ± 0.01 M, for V2365 Oph. The effective temperatures and reddening of the systems have been estimated from Johnson wide-band UBV photometric calibrations. The radii have been measured by simultaneous fitting the UBV light curves using Wilson,Devinney code and are 1.60 ± 0.01 R, for both components of V2080 Cyg and 2.19 ± 0.01 and 0.934 ± 0.004 R, for V2365 Oph. The absolute parameters of the stars in both systems lie within the same ranges in the mass,radius, mass,effective temperature, mass,luminosity and luminosity,effective temperature planes as in detached Algol systems. A comparison between the properties of the systems of interest and the predictions of theoretical evolutionary models is undertaken in the log g,logTeff, log R, log M and radius,log age diagrams. The model predictions match the measured properties of V2080 Cyg for an age of about 5.6 Gyr and a ,solar' metal abundance (Z= 0.019), indicating the components near the end of their core hydrogen-burning phases. However, the position of the components of V2365 Oph on the Hertzsprung,Russell (HR) diagram is best reproduced with evolutionary models for somewhat metal-deficient (Z= 0.004) stars. We found an age of about 700 Myr, with the primary component slightly evolved off the zero-age main-sequence and the secondary one still very close to it. From the basic stellar parameters we have also redetermined the distances to V2080 Cyg and V2365 Oph as 78 ± 1 and 251 ± 8 pc, which are in agreement with, and more accurate than, Hipparcos values. The observations show that at least one of the components of V2365 Oph is an intrinsic variable with a period and peak-to-peak amplitude of 0.07 d and 0.05 mag, respectively. In accordance with its position in the HR diagram, the primary component should be considered as a , Scuti star and it is believed to be the variable star in the system. [source] Transformations between the 2MASS, SDSS, and BVI photometric systems for late-type giantsASTRONOMISCHE NACHRICHTEN, Issue 8 2010E. Yaz Abstract We present colour transformations from Two Micron All Sky Survey (2MASS) photometric system to Johnson-Cousins system and to Sloan Digital Sky Survey (SDSS) system for late-type giants and vice versa. The giant star sample was formed using surface gravity constraints (2 < log g , 3) to Cayrel de Strobel et al.'s (2001) spectroscopic catalogue. 2MASS, SDSS and Johnson-Cousins photometric data was taken from Cutri et al. (2003), Ofek (2008), and van Leeuwen (2007), respectively. The final sample was refined applying the following steps: (1) the data were dereddened, (2) the sample stars selected are of the highest photometric quality. We give two-colour dependent transformations as a function of metallicity as well as independent of metallicity. The transformations provide absolute magnitudes and distance determinations which can be used in space density evaluations at relatively short distances where some or all of the SDSS magnitudes of late-type giants are saturated (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effect of Water Phase Salt Content and Storage Temperature on Listeria monocytogenes Survival in Chum Salmon (Oncorhynchus keta) Roe and Caviar (Ikura)JOURNAL OF FOOD SCIENCE, Issue 5 2007Joong-Han Shin ABSTRACT:, Salmon caviar, or ikura, is a ready-to-eat food prepared by curing the salmon roe in a brine solution. Other seasonings or flavorants may be added, depending upon the characteristics of the product desired. Listeria monocytogenes growth is a potential risk, since it can grow at high salt concentrations (>10%) and in some products at temperatures as low as 3 °C. Ikura was prepared from chum salmon (Oncorhynchus keta) roe by adding food-grade NaCl to yield water phase salt contents (WPS) of 0.22% (no added salt), 2.39%± 0.18%, 3.50%± 0.19%, and 4.36%± 0.36%. A cocktail containing L. monocytogenes (ATCC 19114, 7644, 19113) was incorporated into the ikura at 2 inoculum levels (log 2.4 and 4.2 CFU/g), and stored at 3 or 7 °C for up to 30 d. L. monocytogenes was recovered by plating onto modified Oxford media. Aerobic microflora were analyzed on plate count agar. Samples were tested at 0, 5, 10, 20, and 30 d. L. monocytogenes did not grow in chum salmon ikura held at 3 °C during 30 d at any salt level tested; however, the addition of salt at these levels did little to inhibit Listeria growth at 7 °C and counts reached 5 to 6 logs CFU/g. Components in the salmon egg intracellular fluid appear to inhibit the growth of L. monocytogenes. Total aerobic microflora levels were slightly lower in products with higher salt contents. These results indicate that temperature control is critical for ikura and similar products, but that products with lower salt contents can be safe, as long as good refrigeration is maintained. [source] | |||||||||||||