1,720,984 research outputs found
Detección, caracterización y análisis genotípico de Escherichia coli productor de toxina Shiga en muestras de cuero y carcasa de bovinos en frigoríficos de consumo interno
No full textFil: Cap, Mariana. Instituto De Investigación Tecnología de Alimentos; Argentina.Fil: Rivas, Marta. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Chinen, Isabel. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Servicio de Fisiopatogenia; Argentina
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Capítulo 1 Introducción
No full textThe microbiology of food and, specifically meat, it is a field essential for food safety. Verification of production processes through microbiological analysis is an obligatory step for the release of products intended for human consumption and animal . The information generated regarding of the absence/presence of microorganisms pathogens or the evolution of microorganisms indicators allow evaluating the risk of microbial contamination, implement methods to control its development and prevent the spread of diseases. According to the Argentine Food Code (CAA), meat is defined as "the edible part of the muscles of the declared cattle, sheep, pigs and goats suitable for human consumption by official veterinary inspection before and after the job. The meat includes to all the soft tissues surrounding the skeleton, including its fatty covering, tendons, vessels, nerves, aponeurosis and all those tissues not separated during the operation of the task". Its majority, variable components Depending on the species of origin, they are water (65-80%), protein (16-22%) and fat (1 to 15%). There are also small amounts of nitrogenous substances non-protein (free amino acids, peptides, nucleotides), highly bioavailable minerals, (iron and zinc), vitamins (86, 812, retinol and thiamine), and carbohydrates. Approximately 40% of amino acids that make up the proteins of meat are essential, which makes This product is considered a food of high biological value. Are features provide an environment ideal for bacterial development. Previous to the slaughter, the edible tissues of a healthy animal can be considered sterile, since they are protected from bacterial contamination by leather, which works as an almost perfect cover. However, during slaughter the microorganisms present in the environment, in the hands and utensils, or on fabrics and other surfaces not sterile, they can contaminate them. Microorganisms of importance in meat products can be classified into three groups: alterers, indicators and pathogens.La microbiología de los alimentos y, específicamente de la carne, es un campo fundamental para la inocuidad alimentaria. La verificación de los procesos de producción mediante análisis microbiológicos es un paso obligado para la liberación de productos destinados al consumo humano y animal . La información generada respecto de la ausencia/presencia de microorganismos patógenos o la evolución de microorganismos indicadores permite evaluar el riesgo de contaminación microbiana, implementar
métodos para controlar su desarrollo y prevenir la propagación de enfermedades. Según el Código Alimentario Argentino (CAA), se define a la carne como "la parte comestible de los músculos de los bovinos, ovinos, porcinos y caprinos declarados aptos para la alimentación humana por la inspección veterinaria oficial antes y después de la faena. La carne comprende a todos los tejidos blandos que rodean al esqueleto, incluyendo su cobertura grasa, tendones, vasos, nervios, aponeurosis y todos aquellos tejidos no separados durante la operación de la faena". Sus componentes mayoritarios, variables según la especie de origen, son agua (65-80%), proteína (16-22%) y grasa (1 a 15%). También se encuentran pequeñas cantidades de sustancias nitrogenadas no proteicas (aminoácidos libres, péptidos, nucleótidos), minerales de elevada biodisponibilidad, (hierro y zinc), vitaminas (86, 812, retinol y tiamina), e hidratos de carbono. Aproximadamente el 40% de los aminoácidos que componen las proteínas de la carne son esenciales, lo que hace que este producto sea considerado como un alimento de elevado valor biológico. Estas características proporcionan un ambiente ideal para el desarrollo bacteriano. Previo a la faena, los tejidos comestibles de un animal sano se pueden considerar estériles, ya que se encuentran protegidos de la contaminación bacteriana por el cuero, que funciona como una cubierta casi perfecta. Sin embargo, durante la faena los microorganismos presentes en el ambiente, en manos y utensilios, o en tejidos y otras superficies no estériles, pueden contaminarlos. Los microorganismos de importancia en productos cárnicos pueden clasificarse en tres grupos: alteradores, indicadores y patógenos.Instituto Investigación Tecnología de Alimentos (ITA)Fil: Teitelbaum, David. Minerva Foods; Argentina.Fil: Cap, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Tecnología de Alimentos; Argentina.Fil: Cap, Mariana. Instituto de Ciencia y Tecnología de los Sistemas Alimentarios Sustentables (ICyTeSAS) UEDD INTA-CONICET; Argentina
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Effects of High Hydrostatic Pressure and Beef Patty Formulations on the Inactivation of Native Strains of Shiga Toxin-Producing Escherichia coli O157:H7
No full textThis study aimed to evaluate the effects of beef patty formulations and pressure levels on the inactivation of spoilage microbiota and native Shiga toxin-producing Escherichia coli (STEC) O157:H7. Beef patties were made with different salt and fat content (A: 1% NaCl – 10% fat, B: 2% NaCl – 10% fat, C: 1% NaCl – 20% fat and D: 2% NaCl – 20% fat) and treated at 400 and 600 MPa. STEC reductions after 400 and 600 MPa were 2 and 4 log CFU/g, respectively. STEC inactivation was similar in patties with 10 and 20% of fat content. However, patties with 1% of NaCl showed higher STEC reductions than those made with 2% of NaCl. The baroprotective effect of salt was probably related with the accumulation of compatible solutes, a well-known bacterial response to osmostress. After HPP treatment, all counts of spoilage microbiota were under the detection limit regardless of the formulation.Instituto de Investigación de Tecnología de Alimentos (ITA)Fil: Eccoña Sota, Amparo. Instituto de Ciencia y Tecnología de Sistemas Alimentarios Sustentables (UEDD INTA CONICET); Argentina.Fil: Cap, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Tecnología de Alimentos; Argentina.Fil: Cap, Mariana. Instituto de Ciencia y Tecnología de Sistemas Alimentarios Sustentables (UEDD INTA CONICET); Argentina.Fil: Rodriguez, Anabel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Tecnología de Alimentos; Argentina.Fil: Rodriguez, Anabel. Instituto de Ciencia y Tecnología de Sistemas Alimentarios Sustentables (UEDD INTA CONICET); Argentina.Fil: Speroni Aguirre, Francisco José. Universidad Nacional de La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA) (UNLP - CONICET); Argentina.Fil: Vaudagna Sergio Ramon. Instituto Nacional de Tecnología Agropecuaria (INTA). CIA. Instituto de Investigación Tecnología de Alimentos (ITA); Argentina.Fil: Vaudagna Sergio Ramon. Instituto de Ciencia y Tecnología de Sistemas Alimentarios Sustentables (UEDD INTA CONICET); Argentina.Fil: Speroni Aguirre, Francisco José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA); Argentina
Estrategias de intervención para mitigar el impacto de Escherichia coli productor de toxina Shiga en la cadena cárnica bovina.
Full text linkTesis para obtener el grado de Doctora en Ciencias Veterinarias, de la Universidad de Buenos Aires, en 2021.
Fecha de defensa, 29 de marzo 2022.Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens that can cause bloody diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. The meat contaminated with STEC impacts on the public health due to the risk of making the consumer sick and on the economy due to the loss implied by the rejection of contaminated meat destined for export. In this context, there is a strong demand to evaluate the effectiveness of the antimicrobial treatments available in the country against native STEC O157 and non-O157 strains. The aim of the present study was to evaluate, standardize and promote intervention strategies to reduce the presence of STEC O157 and non-O157 in beef cuts, beef trimmings (raw material for beef burger preparation) and ground beef. For that matter, we conducted three assays. In assay 1, we evaluated the efficacy of lactic acid (LA), peroxiacetic acid (PA), caprylic acid (CA) and electrolyzed water (EW) to reduce STEC in beef cuts. In assay 2, we evaluated the efficacy of LA, CA and gamma irradiation, alone and combined, to reduce STEC in beef trimmings. In assay 3, we evaluated the efficacy of gamma irradiation to reduce STEC in ground beef. In the 3 assays, the effects on the sensory attributes of the most effective interventions on the different meat matrices analyzed were evaluated, and in assays 1 and 2 the effects on physicochemical parameters were also evaluated. The inoculum consisted in a cocktail of native STEC strains that belonged to the following serogroups: O26, O103, O111, O145 and O157. Samples were inoculated with two bacterial concentrations, high and low. Samples with high inoculum (HI) were analyzed by plate count while samples with low inoculum (LI) were analyzed by real-time PCR after an enrichment step. Effectiveness was estimated in terms of log reductions for samples with HI and in terms of reduction of the percentages of positive samples for stx and eae genes in samples with LI. Results from assay 1 demonstrated that from the four interventions evaluated, only CA was effective to reduce STEC. The achieved reductions were 0.8 log CFU/g in samples with HI and 77% in samples with LI. Results from assay 2 demonstrated that the most effective treatment to reduce STEC was 2 kGy of gamma irradiation as the reduction was higher than 5 log CFU/g in samples with HI and of 100% in samples with LI. The combined treatment of LA and gamma irradiation increased STEC lethality in samples with HI but not in samples with LI. Results from assay 3, demonstrated that 1 kGy was enough to reduce 5 log CFU/g in ground beef samples with HI. However, when samples with LI were subjected to that dose it did not achieve a total STEC inactivation. The results of the present study demonstrate the importance of assessing antimicrobial treatments with more than one level of inoculum. Furthermore, increase the knowledge about different strategies to reduce STEC contamination in beef products without significantly affecting nor physicochemical characteristics neither sensory attributes.Escherichia coli productor de toxina Shiga (STEC) es un patógeno de transmisión alimentaria que causa diarrea sanguinolenta, colitis hemorrágica y síndrome urémico hemolítico. La carne contaminada con STEC impacta en el ámbito de la salud pública por el riesgo de enfermar al consumidor y en el ámbito económico por la pérdida que implica el rechazo de la carne contaminada con destino a la exportación. En este contexto, existe una fuerte demanda de evaluar la efectividad de los tratamientos antimicrobianos disponibles en el país frente a cepas nativas de STEC O157 y no O157. El objetivo del presente trabajo fue evaluar, estandarizar y promover estrategias de intervención para reducir la presencia de STEC (O157 y no-O157) en cortes, recortes (materia prima para la preparación de hamburguesas) picada de carne bovina. Para ello, se realizaron 3 ensayos. En el ensayo 1 se evaluó la efectividad de ácido láctico (AL), ácido peroxiacético (AP), ácido caprílico (AC) y agua electroactivada (AE) para reducir STEC en cortes de carne vacuna. En el ensayo 2 se evaluó la efectividad de AL, AC e irradiación, solos y combinados, para reducir la presencia de STEC en recortes de carne bovina y, en el ensayo 3 se evaluó la efectividad de irradiación gamma para reducir STEC en carne bovina picada. En los 3 ensayos se evaluaron los efectos sobre los atributos sensoriales de las intervenciones más efectivas sobre las distintas matrices cárnicas evaluadas y, en los ensayos 1 y 2 también se evaluaron los efectos sobre los parámetros fisicoquímicos. El inóculo consistió en un coctel de cepas autóctonas de STEC pertenecientes a los serogrupos O26, O103, O111, O145 y O157. Las muestras se inocularon con dos concentraciones de bacterias, alta y baja. Las muestras con alta concentración de STEC se analizaron por recuento en placa y las muestras con baja concentración de STEC se enriquecieron y se analizaron por PCR en tiempo real. La efectividad se evalúo en términos de número de reducciones logarítmicas para las muestras con IA y en términos de reducción del porcentaje de muestras positivas para los genes stx y eae en las muestras con IB. Los resultados del ensayo 1 evidenciaron que, de los 4 tratamientos analizados, sólo el AC fue efectivo con reducciones de 0,8 log UFC/g en las muestras con IA y del 77% en las muestras con IB. Los resultados del ensayo 2 evidenciaron que el tratamiento más efectivo fue el de irradiación con 2 kGy con reducciones de más de 5 log UFC/g en las muestras con IA y del 100 % en las muestras con IB. La combinación de AL e irradiación aumentó la letalidad en muestras con IA pero no en muestras con IB. Los resultados del ensayo 3 de las muestras con IA evidenciaron que 1 kGy sería suficiente para reducir 5 log UFC/g en carne bovina picada. Sin embargo, al exponer las muestras con IB a dicha dosis no se alcanzó la inactivación
total. Con respecto a los efectos sobre los parámetros fisicoquímicos y los atributos sensoriales de los productos cárnicos se concluyó que las modificaciones fueron mínimas. Los resultados de este trabajo demuestran la importancia de evaluar la efectividad de los tratamientos antimicrobianos con más de un nivel de inóculo y constituyen un aporte de conocimiento para reducir la contaminación de STEC en carne bovina sin alterar de manera significativa los parámetros fisicoquímicos ni los atributos sensoriales de la misma.Instituto de Investigación de Tecnología de Alimentos (ITA)Fil: Cap, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Tecnología de Alimentos; Argentina
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