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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Nutritional characteristics of New Zealand export lamb and functional properties of selected beef forequarter muscles : a thesis presented in partial fulfilment of the requirements for the degree of Masters of technology in Bioprocess Engineering at Massey University, Palmerston North, New Zealand

Jansen, Eion January 2001 (has links)
Richmond Ltd. has recently undergone a change in strategy, away from the traditional commodity based meat industry, towards the modern food business. To do this, opportunities to add value to their current product range must be identified. This involves the conversion of traditionally low value commodity based products into products that demand a premium. An example of this is converting muscles that are currently used for grinding meat into a further processed convenience food (i.e. ready meals). Another method is to add further value to premium products by making them more appealing to consumers (i.e. nutritional information on labels). This work details investigations into the functional properties of selected beef forequarter muscles (low value commodity products) and the nutritional properties of selected export lamb products (premium products). The functional properties of a number of beef forequarter muscles were measured to identify which had the best potential for further processing applications with respect to ready meals. The functional properties of tenderness, cook loss and shrinkage were measured for the Latissimus Dorsi, Pectorialis Profundus (Point End Brisket), Infraspinatus (Cross Cut Blade), Triceps Brachi Longhead (Main muscle in Bolar Shoulder Clod), Supraspinatus (Chuck Tender), Serratus Ventralis and Triceps Brachi Medialhead (Muscle in Bolar Shoulder Clod. From the tests conducted the Infraspinatus and the Triceps Brachi Longhead have been identified as having the best functional properties with respect to further processing for ready meal applications. As well as conducting tests to identify the forequarter muscles with the best potential for further processing applications, investigations were carried out to identify cooking regimes that would optimise the functional properties. This work confirmed that there are three major chemical reactions, which determine the resultant functional properties of cooked meat. They are the denaturation and aggregation of the myofibrillar proteins and the denaturation and solubilisation of connective tissue (collagen). At around 50°C myosin (45% to 50% of the myofibrillar proteins) denatures, which results in a substantial increase in cook loss and reduction in water holding capacity. At around 60°C collagen (main connective tissue protein) denatures, which results in a substantial increase in tenderness and increase in cook loss. This is because as the collagen denatures it loses it mechanical strength (increase in tenderness) and can no longer support its own structure, and causes it to contract. This contraction causes fluid within the meat and cook loss caused by the denaturation of myosin to be expelled from the meat by compressive forces (squeezed out). At around 70°C actomyosin (22% of the myofibrillar proteins) denatures. This results in a substantial increase in the cook loss and firming of the meat. The increase in cook loss or decrease in water holding capacity that occurs with myofibrillar protein denaturation is due to the fact that when these proteins denature and aggregate their ability to bind water is greatly reduced. From the results of the cooking regime trials it is recommended that for functional property considerations that during the cooking of further processed meat products (i.e. ready meal applications) a meat temperature of 62°C should be aimed for, for the slowest heating region during cooking (usually the centre). This is because it has been identified that a cooking temperature of 65°C should not be exceeded otherwise detrimental effects can occur to the functional properties of the cooked meat. For health concerns a 7D bacterial death reduction has to be achieved. This means that for a cooking temperature of 62°C the meat has to be held at this temperature for at least 5 minutes. Therefore the total cooking time would be the time needed to heat all the meat to 62°C plus 5 minutes to ensure a safe product. The heating or cooking system employed should also ensure that a minimal amount of the meat is heated above 65°C. This can be easily achieved by minimising the external cooking temperature, but long cooking times will result. An industrial cooking process will be a compromise between the cost associated with longer residence time and product functionality. As mentioned earlier another way to add value is to supply nutritional information for selected cuts. Consequentially one of the objectives of this project was to provide some nutritional information for selected meat cuts. Though the primary objective of this part of the project was to develop a method for producing the needed information, so that Richmond N.Z. Ltd. can develop further information on an as needs basis. The nutritional characteristics of a number of export lamb cuts from the saddle region has also been investigated and a method devised to allow further characterisation of other cuts. The method involves breaking down a standard cut into its constituent components (e.g. Frenched rack consists of loin eye, fat cap, intercostals and fatty tissue). The constituent components are tested for their nutritional properties. The frenched rack nutritional properties are calculated from the nutritional properties of the constituents components and the yield data (percentage of each constituent component within a frenched rack) for frenched racks. This method allowed the identification of the main sources of variation for nutritional characteristics. These differences were found to be caused by the lean to fat ratio, not nutritional differences in lean tissue from the same region of lamb (i.e. loin eye and tenderloin very similar nutritionally). The difference in lean to fat ration also accounts for the variation between grades (i.e. PX grade lamb cuts have a higher fat content than YX grade lamb cuts due to PX grade cuts having a higher percentage fat tissue in their cuts). The cuts characterised were the shortloin section (whole section or chop), rack section (whole section or chop), 75mm racks frenched 25mm, boneless loin and tenderloin for both PX and YX grade lamb. The method will be applicable to other regions of lamb (i.e. hindquarter and forequarter) for which nutritional information already exists, but for which yielding data will have to be collected. The method would also be applicable to other species such as beef and venison, but both nutritional data for constituent components and yielding data would have to be collected.
142

Produção científica sobre segurança dos alimentos no contexto da segurança alimentar no Brasil: período de 2000 a 2012 / Scientific production about food safety in the context of food security in Brazil: period 2000-2012

Renata Maturino de Oliveira 30 September 2013 (has links)
O objetivo deste trabalho foi analisar descritiva e criticamente a produção científica brasileira em ‘segurança dos alimentos’, no período de 2000 a 2012, utilizando para as buscas de trabalhos 47 descritores no português brasileiro e língua inglesa. Utilizou as bases de artigos indexados: Scielo - método Google Acadêmico, Scielo método Integrado, CAB Abstract, Scopus, Web of Science, LILACS, Food of Science and food and process e BINAGRI. Do total de trabalhos identificados no tema ‘segurança dos alimentos’ no contexto da Segurança Alimentar, houve predominância de estudos sobre alimentos, manipuladores, equipamentos/utensílios e ambiente; os tipos de estabelecimentos mais frequentemente focados nos estudos foram: restaurantes, churrascarias, lanchonetes e bares; as naturezas de estudo mais utilizadas pelos pesquisadores foram: check-list para avaliar boas práticas de higiene e manipulação, entrevistas, observações in loco e visitas técnicas; houve predomínio de trabalhos provenientes das regiões Sudeste e Sul; as entidades públicas federais e estaduais são as que mais investem nas pesquisas acadêmicas; predominaram trabalhos sobre alimentos, manipuladores e equipamentos/ utensílios e ambiente nas regiões Sudeste e Sul; Apesar da ampla variedade de Objetos de Estudo, quando comparada às Naturezas de Estudo utilizadas pelos pesquisadores, pode ser observado que estão gerando soluções, incremento e inovações para o setor de alimentação, no sentido de aprimoramento dos processos, das BPF e da redução de riscos de ocorrência de DTAs; pode ser observado um baixo número de trabalhos que apresentam intervenções práticas nos estabelecimentos alimentícios utilizados nas pesquisas. / The aim of this research was to make a descriptive and critical analysis of the Brazilian \"food safety\" scientific production from 2000 to 2012, making use of 47 Brazilian Portuguese and English descriptors for the work research. It was based on indexed papers: Scielo - Google Scholar Method, Scielo Integrated Method, CAB Abstract, Scopus, Web of Science, LILACS, Food of Science and food and process and BINAGRI. From all of the papers identified with the \"food safety\" subject, the majority of studies were about food, food handlers, equipment´s/utensils and environment; the types of businesses that were most focused on the studies were: restaurants, steak houses, diners and bars; the types of study that were mostly utilized by the researchers were: check-lists to evaluate good hygienic practices and food manipulation, interviews, in loco observations and technical visits; studies from South and Southwest regions were predominant; public state and federal entities are the ones that invest the most in academic researches; in the South and Southwest regions, studies of food, food handlers and equipment´s/utensils and environments were preponderant; although the broad range of Study Objects, when compared to the nature of study used by the researchers, it can be observed that solutions, enhancements and innovations for the food sector are being created, towards processes and GMP improvement and decrease in the occurrence risk rate of foodborne diseases; it can be observed a low number of papers that present practical interventions on the food businesses that were analyzed on the researches.
143

Contaminação cruzada durante o fatiamento de produto cárneo pronto para o consumo: foco em Listeria monocytogenes / Cross contamination during slicing of a ready-to-eat meat product: focus on Listeria monocytogenes

Daniele Bezerra Faria 01 December 2016 (has links)
Surtos e casos de listeriose reportados mundialmente e associados a produtos cárneos processados prontos para consumo podem ter sido causados pela contaminação cruzada com Listeria monocytogenes ocorrida durante a etapa de fatiamento destes produtos no varejo. Considerando o impacto da contaminação cruzada para a saúde pública, este trabalho teve por objetivo estudar a transferência de L. monocytogenes durante a etapa de fatiamento de rosbife do tipo \"caseiro\", simulando, em laboratório, cenários observados em estabelecimentos comerciais em relação às práticas adotadas durante o fatiamento. Objetivou-se também avaliar o papel do nível da contaminação do produto (baixo e alto) causador da contaminação experimental do fatiador na contaminação cruzada resultante, bem como avaliar se a exposição da cepa de L. monocytogenes a um sanitizante em concentração insuficiente para a sua eliminação influencia a contaminação cruzada observada. A contaminação do fatiador foi obtida por meio do fatiamento de peças de rosbife experimentalmente contaminadas com o patógeno por imersão em uma suspensão de L. monocytogenes contendo 8 log UFC/mL (alto nível de contaminação) e 4 log UFC/mL (baixo nível de contaminação). Os experimentos foram realizados até a obtenção de 200 fatias. As enumerações de L. monocytogenes nas fatias obtidas foram feitas empregando-se um método cultura-dependente (ISO 11290-2:1998) e um método qPCR, calculando-se também as taxas de transferência. Os resultados mostraram que a contaminação dos fatiadores resultou na transferência do patógeno até pelo menos a 120&#170; fatia de uma nova peça de rosbife fatiada posteriormente. Nos experimentos realizados com L. monocytogenes exposta ao sanitizante Oasis Compac 22 Quat em concentração insuficiente para sua eliminação, foi possível enumerar o patógeno até a 200ª fatia de rosbife obtida após a contaminação experimental do fatiador, independentemente do nível de contaminação da peça de rosbife usada para a contaminação do fatiador. Equações matemáticas resultantes, que descrevem os dados experimentais obtidos, apresentaram R2>0,7 e p<0,05, mostrando bom ajuste. Esses resultados ressaltam a importância de medidas para evitar a ocorrência de contaminação cruzada durante a etapa de fatiamento de produtos cárneos prontos para o consumo, bem como da higienização adequada dos equipamentos utilizados, de forma a fornecer produtos seguros para o consumidor. / Outbreaks and cases of listeriosis reported worldwide and associated to ready-to-eat meat products may have been caused by cross contamination with Listeria monocytogenes occurred during the slicing step of these products at retail. Considering the impact of cross-contamination to public health, this study aimed to study the transfer of L. monocytogenes during the slicing step of homemade type roast-beef simulating in the laboratory scenarios seen in commercial establishments. The study also aimed to evaluate the role of product contamination level (low and high) causing the experimental contamination of the slicer in the resulting cross-contamination and to evaluate if the exposure of the L. monocytogenes strain to a sanitizer in insufficient concentration for the elimination influences the observed cross-contamination. Contamination of the slicer was obtained through the slicing of roast-beef pieces experimentally contaminated with the pathogen by immersion in a suspension of L. monocytogenes containing 8 log CFU/ml (high contamination) and 4 log CFU/mL (low contamination). The experiments were carried out to obtain 200 slices. Enumerations of L. monocytogenes in the slices employed a culture-dependent method (ISO 11290-2: 1998) and qPCR method, also calculating transfer rates. The results showed that contamination of slicers resulted in the transfer of the pathogen to at least the 120th slice of a new piece of roast-beef sliced subsequently. In experiments conducted with L. monocytogenes exposed to the sanitizer Oasis Compac 22 Quat in insufficient concentration for its elimination, the pathogen could be enumerated until the 200th slice obtained after the slicer contamination, regardless of the contamination level of the roast beef used for contamination of the slicer. Mathematical equations describing the experimental data presented R2>0.7 and p<0.05, showing good fit. These results underscore the importance of measures to prevent the occurrence of cross contamination during the slicing step of ready-to-eat meat products, as well as the proper cleaning of the equipment used in order to provide safe products to the consumer.
144

Entre ready-made et fiction : la posture d’auteur chez Philippe Thomas / Between Readymade and Fiction : The Authorial Posture in Philippe Thomas

Jaret, Émeline 09 December 2017 (has links)
En 1977, Philippe Thomas (1951-1995) débute un travail qui se situe entre l’art et la littérature et qui conservera cette double dimension d’une œuvre procédant tant du voir que du lire. Il l’élabore en lui donnant une dimension narrative dont l’intermédialité, le réseau de ramifications intertextuelles et l’accumulation de travaux qui relèvent du dispositif construisent un récit à la forme discontinue. Participant d’une écriture des événements et s’appuyant sur une mise en parallèle de la présentation artistique et de l’énonciation, le projet de Thomas est celui d’une fiction du faire qui cherche à éprouver la frontière entre les mondes réel et fictionnel. Notre étude souhaite répondre aux objectifs d’une première monographie d’artiste et s’attache à décrire l’ensemble de l’œuvre de Thomas afin d’en reconstruire le parcours à l’aide d’un certain nombre de notions clés. Elle prend sa source dans la bibliothèque de cet artiste qui définit l’art comme un processus de recherche, comme une expérimentation du langage. C’est l’œuvre en train de se faire que nous observons, en nous intéressant à sa genèse et à ses conditions de réalisation. Et ce, afin de définir la posture d’auteur qui se dessine dans la spécificité d’une pratique artistique demandant la prise en compte tant de l’œuvre que de ses marges. Si le projet de Thomas met en place la disparition de l’auteur par le biais d’un protocole de signature de ses ready-mades, notre thèse rappelle qu’il s’agit d’une absence toute paradoxale : l’artiste caché par ses personnages demeure omniprésent et par là, participe de la redéfinition de l’auteur malgré la déclaration de sa mort une décennie plus tôt. / In 1977, Philippe Thomas (1951-1995) begins a practice situated between art and literature, and his works will conserve this dual dimension by proceeding both from the act of seeing and from the act of reading. Through intermediality, a network of intertextual offshoots, and an apparatus formed by the accumulation of works, he constructs a discontinuous narrative. Participating in event-based writing and relying on parallels between artistic presentation and enunciation, Thomas’ project is a fiction of making that seeks to test the frontier between real and fictional worlds. This study seeks to fulfill the need of a first monograph on the artist, and it describes the entirety of Thomas’ oeuvre so as to reconstruct his artistic career with the aid of a certain number of key notions. My first source is the library of this artist, who defines art as a research process like an experimentation of language. I observe the oeuvre as it is being constructed, by focusing on its genesis and on the conditions of its production. I do this in order to define an authorial posture shaped by the specificity of an artistic practice which requires consideration of both the works it produces and its margins. If Thomas’ project carries out the death of the author through a protocol of signatures of his readymades, my dissertation emphasizes that this is a paradoxical absence: the artist hidden by his personas remains omnipotent, participating in the redefinition of the author in spite of the declaration of his death a decade earlier.
145

Evaluation of the outpatient therapeutic programme for management of severe acute malnutrition in three districts of eastern province , Zambia

Mwanza, Mike January 2013 (has links)
Magister Public Health - MPH / The Outpatient Therapeutic Programme (OTP) is an integrated public health innovation for treating severe acute malnutrition without medical complications in children 6 to 59 months of age as outpatients within their communities using Ready to Use Therapeutic Food with the aim of reducing case fatality rates. The OTP approach is implemented in the three districts in Eastern Province of Zambia namely; Chipata, Katete and Petauke. Since inception of the OTP in the province, an evaluation of the OTP has not been conducted. The study is aimed at assessing the effectiveness of the implementation of the OTP for management of severe acute malnutrition in the three districts of Eastern Province of Zambia.
146

Óleo essencial como antimicrobiano natural em produtos cárneos à base de peito de peru : estudo da transferência de Salmonella Enteritidis durante o fatiamento e do seu comportamento durante a vida útil dos produtos fatiados / Essential oil as natural antimicrobial in turkey breast products : study of Salmonella Enteritidis transfer during slicing and its behaviour during shelf-life of the sliced products

Possas, Arícia Mara Melo, 1989- 03 September 2015 (has links)
Orientadores: Marta Cristina Teixeira Duarte, Guiomar Denisse Posada Izquierdo, Fernando Pérez Rodríguez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-27T10:14:20Z (GMT). No. of bitstreams: 1 Possas_AriciaMaraMelo_M.pdf: 2038081 bytes, checksum: 8baf91fa5300fdd80940e18d382b2468 (MD5) Previous issue date: 2015 / Resumo: Salmonella é um dos patógenos mais importantes relacionados a surtos de origem alimentar que têm como veículos carnes vendidas prontas para o consumo. A contaminação destes produtos pode ocorrer durante o processamento em operações como o fatiamento, embalagem e outros procedimentos que requerem manipulação. O aumento do consumo de produtos à base de carne de peru tem sido verificado mundialmente, pois estes aliam a praticidade dos chamados produtos "ready-to-eat" com o fato de que as carnes de aves são reconhecidas como saudáveis. Outro fator importante que influencia na escolha do consumidor é a presença de conservantes químicos nos produtos alimentícios. A substituição de conservantes químicos por substâncias naturais, como os óleos essenciais, e a incorporação destas em sistemas de embalagens ativas, representa uma alternativa interessante e atende a demanda por produtos mais naturais. Este estudo teve como objetivo desenvolver e aplicar um revestimento incorporado com óleo essencial como antimicrobiano em produtos cárneos à base de peito de peru e avaliar sua atividade contra Salmonella Enteritidis, simulando um sistema de embalagem ativa. Além disso, foi estudada a transferência desta bactéria a produtos de peito de peru durante o fatiamento, para simular a contaminação cruzada em equipamentos utilizados para este procedimento. Também foi avaliado o comportamento de S. Enteritidis durante a vida útil de fatias contaminadas dos produtos cárneos, contendo ou não revestimento de óleo essencial, armazenadas a diferentes temperaturas (10 e 25 °C). Quatro formulações dos produtos cárneos (A, B, C e D) foram estudadas para que fosse possível avaliar como a composição da matriz alimentar influencia no comportamento de S. Enteritidis. Dos quatro óleos essenciais testados in vitro, o óleo essencial de Thymus vulgaris (tomilho) foi o que apresentou menor concentração mínima inibitória (MIC) contra S. Enteritidis, sendo selecionado para ensaios posteriores. Baseando-se em análise sensorial e nos testes de triagem antimicrobiana, uma concentração de 0,8 % (v/m) de óleo essencial de T. vulgaris foi aplicada nos revestimentos para os produtos cárneos. Observou-se transferência de S. Enteritidis durante o fatiamento, a partir das lâminas de corte artificialmente contaminadas (~ 8 log UFC/lâmina) a todas as fatias analisadas (n = 20), de produtos revestidos ou não com emulsão de óleo essencial de T. vulgaris. Diferenças estatísticas foram detectadas em relação à transferência do patógeno nos diferentes tratamentos (p ? 0,05). O comportamento de S. Enteritidis nas fatias durante o armazenamento foi fortemente dependente da temperatura e da composição dos produtos, sendo verificado o crescimento a 25 °C em todas as formulações e tratamentos avaliados. Apenas o produto A propiciou o crescimento do patógeno a 10 °C. Nas fatias dos demais produtos foi verificado um perfil de sobrevivência, com redução das contagens ao longo da vida útil. O óleo essencial de T. vulgaris foi efetivo contra S. Enteritidis, durante o armazenamento de fatias revestidas a 10 °C. Testes finais indicaram que a adição e mistura do óleo essencial juntamente com os outros ingredientes, no processo industrial para obtenção dos produtos cárneos processados, possivelmente resultaria em maior atividade antimicrobiana do mesmo contra S. Enteritidis / Abstract: Salmonella is one of the most important pathogens involved in foodborne outbreaks related to the consumption of ready-to-eat meat products. The contamination of these products can occur during processing operations like slicing, packaging or other handling procedures. The increase in demand for turkey breast based products has been verified worldwide since they combine the convenience of ready-to-eat-products with the fact that poultry meat is recognized as healthy by consumers. The presence of chemical preservatives in food products is another important factor that influences consumer¿s choice. The use of natural substances as antimicrobials, such as essential oils, and their incorporation in active packaging systems represents an interesting alternative to the use of chemical preservatives. The aim of this study was to develop and implement an edible coating incorporated with essential oil as a natural antimicrobial to turkey breast products and to assess its activity against Salmonella Enteritidis, in order to simulate an active packaging system. This study also aimed to evaluate the transfer of S. Enteritidis to turkey breast products during the slicing procedure, simulating a cross-contamination scenario. Pathogen behavior during sliced turkey breast products¿ shelf-life at different storage temperatures (10 e 25 °C) was also evaluated. Four different formulations of products (A, B, C and D) were studied in order to evaluate how the composition of these food matrices can influence the behavior of S. Enteritidis. Among the four essential oils tested in vitro, Thymus vulgaris (thyme) essential oil exhibited the lowest minimum inhibitory concentration (MIC) against the pathogen and it was selected to subsequent assays. Based on sensory analysis and antimicrobial screening tests, 0.8 % (v/w) of T. vulgaris essential oil was applied on the edible coatings to be tested on turkey breast meat products. S. Enteritidis could be transferred during the slicing procedure, from artificially contaminated slicer blades (~ 8 log CFU/blade) to all slices microbiologically analyzed (n = 20), of products previously coated and not coated with T. vulgaris essential oil. Statistical differences were detected regarding pathogen transfer in the different treatments (p ? 0.05). S. Enteritidis behavior on slices during storage was strongly dependent on temperature and products composition. Growth was verified in slices of all formulations and treatments during storage at 25 °C. Only one product was susceptible to pathogen growth at 10 °C (product A). In the slices of the other three products (B, C and D) a survival pattern was observed, with reductions of S. Enteritidis counts during shelf-life. T. vulgaris essential oil was effective against S. Enteritidis during storage of slices at 10 °C. Final tests indicated that the addition of T. vulgaris essential oil with the other ingredients, during the industrial manufacture process of turkey breast products, probably would result in higher antimicrobial activity against S. Enteritidis. / Mestrado / Ciência de Alimentos / Mestra em Ciência de Alimentos
147

Freqüência de Listeria monocytogenes em Mortadelas e Comportamento Durante o Processamento Industrial e Estocagem / Listeria monocytogenes: frequency and behavior in \"mortadella\" during commercial processing and storage

Luciano dos Santos Bersot 30 May 2000 (has links)
A importância da Listeria monocytogenes como patógeno veiculado por alimentos, causador de grave quadro de infecção é bem conhecida. Devido a sua grande capacidade de sobrevivência às condições adversas do ambiente, o presente trabalho teve como objetivos verificar a freqüência de L. monocytogenes em mortadelas comercializadas no município de São Paulo, SP; avaliar o comportamento de 2 níveis de inóculos de L. monocytogenes frente ao processamento térmico de mortadelas de 2 formulações em diferentes condições de estocagem e avaliar o comportamento de L. monocytogenes naturalmente presente em mortadelas fatiadas, embaladas a vácuo, comercializadas e estocadas sob refrigeração, durante sua vida de prateleira. As amostras foram analisadas pelos métodos de Presença/Ausência ou NMP/g. Verificou-se que 26,7% das amostras de mortadelas analisadas foram positivas para L. monocytogenes. O processamento térmico convencional aplicado na cocção das mortadelas (74ºC no ponto mais frio) foi suficiente para redução dos inóculos em até 3 ciclos log independente da formulação do produto. A temperatura de estocagem, refrigeração ou temperatura ambiente, não interferiu na recuperação do microrganismo. Nas mortadelas fatiadas e embaladas a vácuo foi observado aumento médio de 2,5 ciclos log do NMP de L. monocytogeneslg durante a vida de prateleira do produto, com níveis de L. monocytogenes próximos a 2,0 log NMP/g no final da vida de prateleira do produto. De acordo com os resultados obtidos concluiu-se que L. monocytogenes é um patógeno freqüente em mortadelas; o tratamento térmico de mortadelas é suficiente para redução de até 3 ciclos logarítmicos de L. monocytogenes, não tendo sido observada presença do microrganismo durante estocagem por 30 dias e que mortadelas fatiadas e embaladas a vácuo mantidas sob refrigeração são susceptíveis a multiplicação de L. monocytogenes durante sua estocagem refrigerada, representando um risco à população susceptível. / L. monocytogenes is an important foodborne pathogen that can cause life threating infections. The importance of L. monocytogenes as a foodborne pathogen is well known. Its capacity to resist to adverse environmental conditions makes this microorganism a cause of concern for the food industry. The objectives of this study were to evaluate: the incidence of L. monocytogenes in mortadella samples commercialised in São Paulo, SP, BR; the behaviour of 2 leveis of L. monocytogenes during the processing of 2 formulations of the product stored at difterent conditions and the behaviour of indigenous L. monocytogenes present in vaccum-packed sliced mortadella during the shelf life of the product. Samples were analised by the Presence/Absence technique or By MPN. 26.7% of the mortadella samples were positive for L. monocytogenes. The conventional cooking process (74°C in the coldest point) was sufficient to reduce the population of the microorganism in up to 3 log and the formulation of the product did not interfere with this reduction. L. monocytogenes was not detected during storage of the product for up to 30 days under cold storage (5-8°C) or room temperature (25°C). The vaccum-packed sliced product showed a mean increase of 2.5 log of MPN/g during its shelf life with the bacterium reaching populations around 2 log MPN/g by the end of the período It could be concluded that L. monocytogenes is very frequent in mortadellas; for this product the cooking process is sufticient to reduce up to 3 log of L. monocytogenes. This microorganism could not be recovered during storage for up to 30 days, indicating no sub-Iethal damage. The vaccum-packed sliced product stored under refrigeration is susceptible to L. monocytogenes growth and can be considered risky to susceptible population.
148

Vegetais minimamente processados prontos para o consumo: influência da etapa de desinfecção na inativação de Salmonella Typhimurium, na ocorrência da contaminação cruzada e na avaliação quantitativa de risco microbiológico em relação a este patógeno / Minimally processed ready-to-eat vegetables: influence of washing-disinfection step on Salmonella Typhimurium inactivation, on occurrence of cross-contamination and on quantitative microbiological risk assessment regarding this pathogen

Daniele Fernanda Maffei 29 April 2016 (has links)
Dados mundiais apontam haver uma associação entre o aumento do comércio de vegetais minimamente processados prontos para o consumo (VPC) e o aumento da ocorrência de surtos de enfermidades transmitidas por alimentos. Durante o processamento industrial de VPC, a desinfecção é a principal etapa de inativação de micro-organismos patogênicos presentes, mas nessa etapa também pode ocorrer contaminação cruzada, com transferência de contaminantes de produtos contaminados para não-contaminados. Neste trabalho, foram coletadas informações sobre as práticas empregadas na etapa de desinfecção em dez importantes indústrias produtoras de VPC no Estado de São Paulo, avaliando-se, em seguida, a influência dessas práticas na qualidade microbiológica dos produtos e na inativação de Salmonella Typhimurium, bem como na ocorrência de contaminação cruzada por este patógeno. Um modelo de avaliação quantitativa de risco microbiológico foi elaborado para estimar o impacto da contaminação cruzada durante a etapa de desinfecção no risco de infecção por Salmonella devido ao consumo de VPC. Observou-se que, em todas as indústrias visitadas, a desinfecção dos vegetais era feita com produtos à base de cloro em concentrações de 50 a 240 mg/L, que resultava em redução de até 1,2 log na carga microbiana dos vegetais que entravam na linha de processamento. Ao avaliar a influência das características da água de processamento (pH, temperatura, concentração de matéria orgânica e concentração de dicloroisocianurato de sódio) e do tempo de contato entre a água clorada e os vegetais na redução de Salmonella, observou-se que a concentração do produto à base de cloro foi o parâmetro que apresentou maior influência (p<0.05). Concentrações de dicloroisocianurato de sódio acima de 10 mg/L foram necessárias para controle da contaminação cruzada durante a etapa de lavagem. O modelo de avaliação de risco construído indicou quantitativamente haver uma relação entre a concentração de dicloroisocianurato de sódio na água de desinfecção e o risco de ocorrência de surtos causados por Salmonella em VPC. Cenários simulando uso de dicloroisocianurato de sódio em concentrações abaixo de 5 mg/L indicaram que mais de 96% dos casos preditos de infecção por Salmonella poderiam ser atribuídos à ocorrência de contaminação cruzada, enquanto que em cenários com concentrações acima de 50 mg/L, casos de infecção devidos à contaminação cruzada não foram preditos. Estes resultados mostram que o controle da qualidade da água e o monitoramento da concentração de sanitizante na etapa de desinfecção são essenciais para evitar a ocorrência de contaminação cruzada e garantir a produção de VPC seguros para o consumo. / Surveillance data in several countries show an association between consumption of minimally processed ready-to-eat (RTE) vegetables and increased occurrence of foodborne diseases outbreaks. During RTE vegetables processing, washing-disinfection is the main step aiming to ensure inactivation of pathogenic microorganisms, but also is the step in which cross-contamination may occur, with transfer of contaminants from contaminated to non-contaminated products. In this study, we collected information on the practices employed during the washing-disinfection step in ten RTE vegetables processing plants located in the State of Sao Paulo, Brazil, and evaluated the influence of these washing practices on the microbial quality of the products and inactivation of Salmonella Typhimurium, as well as on the occurrence of cross-contamination by this pathogen. A quantitative microbial risk assessment model was built in order to estimate the impact of cross-contamination during the washing step on the risk of infection by Salmonella due to the consumption of RTE vegetables. In all visited processing plants, the disinfection step was done using chlorine-based products, in concentrations ranging from 50 to 240 mg/L, achieving a reduction of up to 1.2 log in the microbial load of vegetables entering the processing line. When the influence of washing water parameters (pH, temperature, organic load and sodium dichloroisocyanurate concentration) and time of contact between chlorinated water and vegetables on reduction of Salmonella were evaluated, sodium dichloroisocyanurate concentration influenced the most (p<0.05). Concentrations above 10 mg/L were necessary for avoiding cross-contamination during washing step. The risk assessment model indicated quantitatively a relationship between sodium dichloroisocyanurate concentration and the risk of illness caused by Salmonella in RTE vegetables. When simulation was done with less than 5 mg/L of sodium dichloroisocyanurate, most (>96%) of the illnesses arose from cross-contamination. However, when the concentration was 50 mg/L or higher, no illnesses arising from cross-contamination were predicted. These results show that controlling the quality of the water and monitoring the concentration of the sanitizer in the disinfection step are essential to avoid occurrence of cross contamination and ensure production of RTE vegetables that are safe for consumption.
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Rekonstrukce repetitivních elementů DNA / Reconstruction of Repetitive Elements in DNA

Hypský, Jan January 2018 (has links)
Eukaryotic genomes contain a large number of repetitive structures. Their detection and assembly today are the main challenges of bioinformatics. This work includes a classification of repetitive DNA and represents an implementation of a novel de novo assembler focusing on searching and constructing LTR retrotransposons and satellite DNA. Assembler accepts on his input short reads (single or pair-end), obtained from next-generation sequencing machines (NGS). This assembler is based on Overlap Layout Consensus approach.
150

The food safety knowledge of street vendors and the food safety compliance of their food service facilities, Johannesburg, South Africa

Oladipo-Adekeye, Oluwakemi Taiwo 01 1900 (has links)
The inadequate food safety knowledge by street food vendors have been a challenge encountered in ensuring safety of street foods. The aim of this study was to assess the food safety knowledge of street food vendors in the Johannesburg metropolis and to evaluate the conformance and monitoring of their street food vending facilities in accordance to regulations governing general hygiene requirements for food premises in South Africa. A cross sectional survey was conducted in which 315 street food vendors and 155 street food vending facilities were observed using a questionnaire instrument and observational checklist, respectively. The majority (61.3%) of the street food vendors were females and most (64.1%) of them had not attended a food safety training course. Only a few (12.1%) street food vendors knew the correct minimum internal cooking temperature for stuffed chicken, while less than half knew the correct temperature for cold and hot holding of ready-to-eat foods, 40% and 39% respectively. The majority of them have never heard of Salmonella (92.7%), Campylobacter (95.2%), Listeria (57.1%), Clostridium (94.3%), or Staphylococcus (87.6%). Up to 52% street food vendors had moderate food safety knowledge. Most of the street food vending facilities (68.3%) had been inspected by health inspectors and only 17% of street food vending facilities had low level of compliance to regulations governing general hygiene requirements for food premises and the transport of food in South Africa. The overall food safety knowledge of street food vendors in Johannesburg metropolis was moderate. The level of compliance and monitoring of street food vending facilities to regulations governing general hygiene requirements for food premises in South Africa was satisfactory. Street food vendors should be trained on internal cooking temperature, hot and cold storage temperature of ready-to-eat foods, and food pathogens such as Salmonella, Campylobacter, Listeria, Clostridium, and Staphylococcus / Life and Consumer Sciences / M. Cons. Sci.

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