Metodología para realizar estudios de evidencia microbiológica en plantas procesadoras de alimentos

Metodología para realizar estudios de evidencia microbiológica en plantas procesadoras de alimentos. Se diseñó una metodología para realizar estudios de evidencia microbiológica en plantas procesadoras de alimentos. La metodología consta de seis pasos: definición del objetivo general del estudio, visita a la planta respectiva, diseño de un plan de muestreo, escogencia de los análisis microbiológicos, recolección de los datos, y análisis y utilización de los resultados y conclusiones. Para cada uno de los pasos se describe su objetivo, filosofía y procedimientos asociados. La aplicación de esta metodología permite obtener una serie de conclusiones importantes con respecto a evidencia microbiológica, que sirven como base para diseñar e implementar los sistemas HACCP, pues brindan información específica y propia del ambiente de proceso donde se realizó el estudio

Calidad, durante el almacenamiento, de huevos de gallina (Gallus gallus domesticus) recubiertos con aceite

Introduction: Eggs are one of the main foods providing nutrients to the world population, however, they rapidly loose quality. For the egg industry it would be beneficial to have technological alternatives to increase the shelf life, such as coatings that are applied to prevent quality loss. Objective: To evaluate the effect of the application of oil coatings on the physicochemical, microbiological, and sensory quality of hen eggs during storage. Methods: We applied, by immersion, coatings of deodorized medicinal grade mineral oil or palm and soybean olein with TBHQ 0,02% to category A Isa Brown hen eggs from a local producer, without prior cleaning, washing or disinfection. After a 6-hour drainage, we stored eggs at 21°C and 43% RH. We measured selected quality parameter every 7 days for a total of 42 days and statically compared trends over time for coated and uncoated eggs. Sensory analysis was also carried out using paired comparisons tests for fresh and coated eggs stored for a certain time. We used a hedonic scale for general acceptance of coated and uncoated eggs after 35 days of storage. Results: The evaluated coatings did not affect the normal behavior of the color and pH of the yolk, the Haugh units, the resistance to rupture and the total aerobic and yeast and mold counts during storage, while retarding the deterioration related to the yolk index, pH of the white and overall mass loss. In addition, the application of the coatings helped keep flavor perception of stored eggs when compared with fresh eggs; resulted in eggs with the same smell and adhesiveness as the uncoated egg; gave shine, and did not negatively influence external sensory acceptance. Conclusion: The shelf life of eggs during storage can be extended with the application of mineral or palm oil coatings.Introducción: El huevo, uno de los principales alimentos que aporta nutrientes a la población mundial, pierde su calidad de forma acelerada en estado fresco.  Para la industria del huevo sería beneficioso contar con alternativas tecnológicas que permitan aumentar su vida útil, como la utilización de recubrimientos para prevenir su deterioro. Objetivo: Evaluar el efecto de la aplicación de recubrimientos de aceite sobre la calidad fisicoquímica, microbiológica y sensorial de huevos de gallina en almacenamiento. Métodos: Por inmersión, aplicamos recubrimientos de aceite mineral grado medicinal desodorizado o de oleína de palma y soya con TBHQ 0,02% a huevos de gallina Isa Brown categoría A de un productor local, sin previa limpieza, lavado o desinfección.  Luego de dejar escurrir por 6 horas los almacenamos en una cámara a 21°C y 43% HR. Medimos los parámetros de calidad seleccionados cada 7 días por un total de 42 días y comparamos estadísticamente las tendencias en el tiempo para los huevos recubiertos y sin recubrimiento.  También realizamos un análisis sensorial mediante comparaciones pareadas para huevo fresco y huevo recubierto almacenado por determinado tiempo y una medición de aceptación general por medio de una escala hedónica a los 35 días de almacenamiento. Resultados: Los recubrimientos evaluados no afectaron el comportamiento normal del color y pH de la yema, las unidades Haugh, la resistencia a la ruptura y los recuentos total aerobio y de mohos y levaduras durante el almacenamiento, al tiempo que retardaron el deterioro relacionado con el índice de yema, el pH de la clara y la pérdida de masa. Además, la aplicación de dichos recubrimientos permite mantener la percepción del sabor del huevo almacenado al compararlo con huevo fresco; provee huevos con el mismo olor y adhesividad que el huevo sin recubrimiento; otorga brillo y no influyen negativamente en su aceptación sensorial externa.  Conclusión: La vida útil del huevo durante su almacenamiento puede alargarse con la aplicación de recubrimientos de aceite mineral o de palma

Comparación de indicadores microbiológicos en sistemas de cultivo de tomate convencional o hidropónico

Introduction: Consumption of fresh tomatoes has increased over the years and production systems (conventional or hydroponic), harvest and post-harvest practices, irrigation water and harvest containers, can affect the microbiological quality of the final product. Objective: To compare the microbiological quality of the cultivated or harvested fruit, the irrigation water, and the harvest containers in two tomato production farms (conventional and hydroponic). Methods: We carried out three sampling visits in each farm (repetitions), taking, in each repetition, 3 tomatoes of each type (composite sample), 50 ml of irrigation water and swabbing 50cm2 of the surface of three harvest containers (composite sample). We determined indicator microorganisms such as total aerobic mesophilic count, mold and yeast count, total coliforms, thermotolerant coliforms and E. coli. Presence of Listeria monocytogenes was also analyzed in fruits. We applied student's t-tests at a significance level of 5%. Results: Total aerobic mesophilic and mold and yeast counts of hydroponic tomato were significantly lower than in conventional tomato, while no difference in total coliform counts and E. coli was detected. L. monocytogenes was absent in all samples. The total aerobic mesophilic count was higher in the harvest containers of the conventional farm. In both farms, irrigation water was not considered a source of contamination since it had very low levels of total coliforms, thermotolerant coliforms, and E. coli. Finally, an adequate control during harvesting was presumed, having found no difference in the microbiological indicators between the cultivated and harvested tomato. Conclusion: Hydroponic tomatoes are more likely to have a better microbiological profile and longer shelf life compared to conventionally grown tomatoes, evidencing the importance of environmental control and cleaning and disinfection of all elements used in the farming, harvesting and postharvest processes.Introducción: El consumo de tomate fresco ha ido en aumento a través de los años y los sistemas de cultivo (convencional o hidropónico), las prácticas de cosecha y poscosecha, el agua de riego y los contenedores pueden incidir sobre su calidad microbiológica. Objetivo: Comparar la calidad microbiológica de la fruta cultivada o cosechada, del agua de riego y de los contenedores de cosecha en dos fincas de producción de tomate (convencional e hidropónica). Métodos: Realizamos tres muestreos a cada finca (repeticiones), tomando, en cada repetición, 3 tomates de cada tipo que conformaron una muestra compuesta, 50 ml de agua de riego e hisopando 50cm2 de la superficie de tres contenedores de cosecha (muestra compuesta). Determinamos los indicadores microbiológicos de recuento total aerobio mesófilo, recuento de hongos filamentosos y levaduras, coliformes totales, coliformes termotolerantes y E. coli. Además, analizamos la presencia de Listeria monocytogenes en los frutos. Aplicamos pruebas de t-student a un nivel de significancia del 5%. Resultados: Los recuentos total aerobio mesófilo y hongos filamentosos y levaduras del tomate hidropónico fueron significativamente menores que en el tomate convencional, mientras que no hubo diferencia en los recuentos de coliformes totales y E. coli, además L. monocytogenes estuvo ausente en todas las muestras. El recuento total aerobio mesófilo fue mayor en los contenedores de cosecha de la finca convencional.  En ambas fincas el agua de riego no se consideró fuente de contaminación pues tuvo niveles muy bajos de coliformes totales, coliformes termotolerantes y E. coli.  Finalmente, se presume un control adecuado en las fincas durante la cosecha, al no haber encontrado diferencia en los indicadores microbiológicos entre el tomate cultivado y el cosechado. Conclusión: Los tomates hidropónicos presentan mayor probabilidad de tener un mejor perfil microbiológico y mayor vida útil en comparación con los tomates cultivados de forma convencional, evidenciando la importancia del control ambiental y la limpieza y desinfección de todos los insumos utilizados en los procesos de cultivo, cosecha y poscosecha

The SAURON project. II. Sample and early results

Early results are reported from the SAURON survey of the kinematics and stellar populations of a representative sample of nearby E, S0 and Sa galaxies. The survey is aimed at determining the intrinsic shape of the galaxies, their orbital structure, the mass-to-light ratio as a function of radius, the age and metallicity of the stellar populations, and the frequency of kinematically decoupled cores and nuclear black holes. The construction of the representative sample is described, and its properties are illustrated. A comparison with long-slit spectroscopic data establishes that the SAURON measurements are comparable to, or better than, the highest-quality determinations. Comparisons are presented for NGC 3384 and NGC 4365 where stellar velocities and velocity dispersions are determined to a precision of 6 km/s, and the h3 and h4 parameters of the line-of-sight velocity distribution to a precision of better than 0.02. Extraction of accurate gas emission-line intensities, velocities and line widths from the datacubes is illustrated for NGC 5813. Comparisons with published line-strengths for NGC 3384 and NGC 5813 reveal uncertainties of < 0.1 A on the measurements of the Hbeta, Mgb and Fe5270 indices. Integral-field mapping uniquely connects measurements of the kinematics and stellar populations to the galaxy morphology. The maps presented here illustrate the rich stellar kinematics, gaseous kinematics, and line-strength distributions of early-type galaxies. The results include the discovery of a thin, edge-on, disk in NGC 3623, confirm the axisymmetric shape of the central region of M32, illustrate the LINER nucleus and surrounding counter-rotating star-forming ring in NGC 7742, and suggest a uniform stellar population in the decoupled core galaxy NGC 5813.Comment: 20 pages, 17 figures. To be published in MNRAS. Version with full resolution images available at http://www.strw.leidenuniv.nl/~dynamics/Instruments/Sauron/pub_list.htm

A High Resolution Study of the HI-H2 Transition across the Perseus Molecular Cloud

To investigate the fundamental principles of H2 formation in a giant molecular cloud (GMC), we derive the HI and H2 surface density (Sigma_HI and Sigma_H2) images of the Perseus molecular cloud on sub-pc scales (~0.4 pc). We use the far-infrared data from the Improved Reprocessing of the IRAS Survey and the V-band extinction image provided by the COMPLETE Survey to estimate the dust column density image of Perseus. In combination with the HI data from the Galactic Arecibo L-band Feed Array HI Survey and an estimate of the local dust-to-gas ratio, we then derive the Sigma_H2 distribution across Perseus. We find a relatively uniform Sigma_HI ~ 6-8 Msun pc^-2 for both dark and star-forming regions, suggesting a minimum HI surface density required to shield H2 against photodissociation. As a result, a remarkably tight and consistent relation is found between Sigma_H2/Sigma_HI and Sigma_HI+Sigma_H2. The transition between the HI- and H2-dominated regions occurs at N(HI)+2N(H2) ~ (8-14) x 10^20 cm^-2. Our findings are consistent with predictions for H2 formation in equilibrium, suggesting that turbulence may not be of primary importance for H2 formation. However, the importance of a warm neutral medium for H2 shielding, an internal radiation field, and the timescale of H2 formation still remain as open questions. We also compare H2 and CO distributions and estimate the fraction of "CO-dark" gas, f_DG ~ 0.3. While significant spatial variations of f_DG are found, we do not find a clear correlation with the mean V-band extinction.Comment: updated to match the final version published in April 201

Serologic markers of Chlamydia trachomatis and other sexually transmitted infections and subsequent ovarian cancer risk: Results from the EPIC cohort

A substantial proportion of epithelial ovarian cancer (EOC) arises in the fallopian tube and other epithelia of the upper genital tract; these epithelia may incur damage and neoplastic transformation after sexually transmitted infections (STI) and pelvic inflammatory disease. We investigated the hypothesis that past STI infection, particularly Chlamydia trachomatis, is associated with higher EOC risk in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort including 791 cases and 1669 matched controls. Serum antibodies against C. trachomatis, Mycoplasma genitalium, herpes simplex virus type 2 (HSV-2) and human papillomavirus (HPV) 16, 18 and 45 were assessed using multiplex fluorescent bead-based serology. Conditional logistic regression was used to estimate relative risks (RR) and 95% confidence intervals (CI) comparing women with positive vs. negative serology. A total of 40% of the study population was seropositive to at least one STI. Positive serology to C. trachomatis Pgp3 antibodies was not associated with EOC risk overall, but with higher risk of the mucinous histotype (RR = 2.30 [95% CI = 1.22-4.32]). Positive serology for chlamydia heat shock protein 60 (cHSP60-1) was associated with higher risk of EOC overall (1.36 [1.13-1.64]) and with the serous subtype (1.44 [1.12-1.85]). None of the other evaluated STIs were associated with EOC risk overall; however, HSV-2 was associated with higher risk of endometrioid EOC (2.35 [1.24-4.43]). The findings of our study suggest a potential role of C. trachomatis in the carcinogenesis of serous and mucinous EOC, while HSV-2 might promote the development of endometrioid disease

Heart Rate Variability Dynamics for the Prognosis of Cardiovascular Risk

Statistical, spectral, multi-resolution and non-linear methods were applied to heart rate variability (HRV) series linked with classification schemes for the prognosis of cardiovascular risk. A total of 90 HRV records were analyzed: 45 from healthy subjects and 45 from cardiovascular risk patients. A total of 52 features from all the analysis methods were evaluated using standard two-sample Kolmogorov-Smirnov test (KS-test). The results of the statistical procedure provided input to multi-layer perceptron (MLP) neural networks, radial basis function (RBF) neural networks and support vector machines (SVM) for data classification. These schemes showed high performances with both training and test sets and many combinations of features (with a maximum accuracy of 96.67%). Additionally, there was a strong consideration for breathing frequency as a relevant feature in the HRV analysis

Heart Rate Variability Dynamics for the Prognosis of Cardiovascular Risk

Statistical, spectral, multi-resolution and non-linear methods were applied to heart rate variability (HRV) series linked with classification schemes for the prognosis of cardiovascular risk. A total of 90 HRV records were analyzed: 45 from healthy subjects and 45 from cardiovascular risk patients. A total of 52 features from all the analysis methods were evaluated using standard two-sample Kolmogorov-Smirnov test (KS-test). The results of the statistical procedure provided input to multi-layer perceptron (MLP) neural networks, radial basis function (RBF) neural networks and support vector machines (SVM) for data classification. These schemes showed high performances with both training and test sets and many combinations of features (with a maximum accuracy of 96.67%). Additionally, there was a strong consideration for breathing frequency as a relevant feature in the HRV analysis

The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description

On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2-7 m, while providing data at sub-mm to mm scales. We report on SuperCam's science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.In France was provided by the Centre National d'Etudes Spatiales (CNES). Human resources were provided in part by the Centre National de la Recherche Scientifique (CNRS) and universities. Funding was provided in the US by NASA's Mars Exploration Program. Some funding of data analyses at Los Alamos National Laboratory (LANL) was provided by laboratory-directed research and development funds

Determinants of penetrance and variable expressivity in monogenic metabolic conditions across 77,184 exomes

Penetrance of variants in monogenic disease and clinical utility of common polygenic variation has not been well explored on a large-scale. Here, the authors use exome sequencing data from 77,184 individuals to generate penetrance estimates and assess the utility of polygenic variation in risk prediction of monogenic variants