O Sistema Agroindustrial do Café passou por mudanças significativas em sua organização e nas estratégias adotadas pelos agentes produtivos. As transformações desencadearam a possibilidade de subcontratação de firmas especializadas em prestação de serviços de mecanização agrícola da colheita e, consequentemente, o desempenho econômico e as formas de coordenação do cafeicultor se modificaram. O objetivo da presente dissertação é identificar os determinantes da escolha de subcontratar os serviços na transação de colheita mecanizada do Sistema Agroindustrial do Café no Brasil. A investigação é construída com base em uma abordagem quantitativa com uma survey analisada por uma regressão probit, além de ser complementada com uma abordagem qualitativa. Os resultados encontrados apontaram que o sistema produtivo possui setores com diferentes graus de concentração, padrões tecnológicos, formações de preços e mecanismos de coordenação distintos ao longo da cadeia, assim como levantaram a existência de conflitos na transação de colheita mecanizada a partir do ambiente institucional e organizacional. Na sequência, o modelo econométrico validou a hipótese da especificidade de ativo e incerteza do argumento de alinhamento eficiente da teoria da Economia de Custos de Transação, além de validar o aspecto de path dependence e apontar os determinantes da subcontratação como sendo o nível de escolaridade elevado do cafeicultor e a adoção de contratos como forma de coordenação de outras transações. / The Agribusiness system of coffee has been changing its organization and strategies along the chain. The changes have risen opportunities to outsourcing harvest mechanization services with specialized firms and, consequently, economic performance and coordination mechanism in coffee grower\'s transactions have modified. The investigation aims to analyze the determinants of the choice of outsourcing the services of harvest mechanization transaction of the Agribusiness system of coffee in Brazil. The study is based on a quantitative approach with a survey being performed with a probit regression, and also, a qualitative approach to explore the whole scenario of the phenomenon. The results indicate that the coffee chain has different levels of market concentration, technological patterns, price formation, and different coordination mechanisms along the chain, as well as have showed the existence of conflicts between the institutional and organizational environment of the harvest mechanization transaction. The findings of the econometric model have validated the path dependence aspect and the hypothesis of the asset specificity and uncertainty of the efficient alignment argument of the Transaction Cost Economics. The model has pointed out the level of schooling and the adoption of contracts as a way of coordinating other transactions as determinants of outsourcing of harvest mechanization transaction.

Orientadores: Paulo Ademar Martins Leal, Sylvio Luís Honório / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-20T12:03:10Z (GMT). No. of bitstreams: 1 Oliveira_DenizeCristineRodriguesde_M.pdf: 1514216 bytes, checksum: 5b23bd3986cd65f29487a7dbef3936db (MD5) Previous issue date: 2012 / Resumo: Devido a uma tendência da população mundial em adquirir hábitos de vida mais saudáveis, cresce o consumo de hortaliças folhosas a cada ano, juntamente com a exigência da população pela qualidade total e segurança do alimento. Lactuca sativa L. (Asteraceae) é considerada a mais importante das hortaliças no grupo das folhosas, sendo também a mais produzida e mais consumida no Brasil. Um dos entraves é a alta perecibilidade do produto, ocorrendo perdas ao longo de toda cadeia produtiva. O objetivo principal deste trabalho foi estudar a influência de sistemas de colheita diferenciada em quatro tipos de alface (Repolhuda Americana 'Graciosa', Solta Crespa 'Vanda', Solta Lisa 'Marcela' e Solta Crespa 'Lavínia'), visando a melhor forma de manutenção da qualidade. Foram estudados os sistemas de colheita diferenciada com raiz e com corte que minimizem o dano por corte, denominados de corte 1 e 2, realizados na transição caule raiz, e entre o início da zona radicular e a primeira inserção de folha, comparado com o processo de colheita convencional. A qualidade do produto foi determinada por análises físico-químicas e sensoriais. A interpretação dos resultados foi realizada por análise de variância e teste de Tukey a 95% de confiabilidade, além de análise de componentes principais. Concluiu-se que para todas as características avaliadas houve degradação da qualidade ao longo do período de armazenamento. Para a alface 'Graciosa' o sistema de colheita realizado pelo tratamento corte 1 (transição caule raiz) não é recomendado, sendo os demais iguais para manutenção da qualidade. Já para a alface 'Vanda' recomenda-se os sistemas corte do produtor e corte 1, pois obtiveram uma degradação lenta dos parâmetros físico-químicos. Para a alface 'Marcela' recomenda-se o sistema de colheita representado pelos tratamentos com raiz e corte 2 (entre o início da zona radicular e a primeira inserção de folha). Para a alface 'Lavínia', recomenda-se o sistema de colheita representado pelos tratamentos com raiz e corte do produtor.Houve redução da qualidade das plantas de alface do 1° ao 5° dia de armazenamento, sendo que no 6° dia apenas a alface 'Lavínia' no tratamento com raiz e corte 2 foram consideradas aceitáveis No 9° dia de armazenamento todas as amostras foram consideradas impróprias para o consumo / Abstract: Leafy vegetables consumption increases every year due to a tendency of the world's population in acquiring a healthier lifestyle. Lactuca sativa L. (Asteraceae) is considered the most importantin the group of leafy vegetables. It is almost exclusively used, in natura, as a fresh vegetable. Lettuce (Lactuca sativa L.) is the leafy vegetable most widely produced and consumed in Brazil, main production areas are concentrated in green belts next to big consumercenters, to avoid losses caused to its perishability. In addition, is also increased every year the demand of the population for total quality and safety of the food. This project aims to integrate the stages of harvesting of four different types (Repolhuda Americana 'Graciosa', SoltaCrespa 'Vanda', Solta Lisa 'Marcela' e SoltaCrespa 'Lavínia'), suggesting that the procedures for collection, be carried out with minimum handling, least loss of mass and exuberance; keeping the quality and extending the shelf-life, respecting the legal standards of use. Differentiated harvest was studied, with root and cutting that minimize the damage and mass loss, when compared to traditional harvesting procedures. The product's quality were determined by physical-chemical and sensorial analyses. Interpretation of the results was performed by analysis of variance and Tukey test at 95% reliability, as well as principal component analysis, with the aid of programsAssistat version 7.6 beta (SILVA, 2011) and R version 2.14.1 (R, 2011). It was found that for all attributes, quality degradation has occurred during the storage period. For 'Graciosa' lettuce, the worst harvest system studied was the cutting 1. As for the 'Vanda' lettuce, the best cuts were the producer cut and cutting 1, since it had a slow degradation of the physical chemical parameters. For the 'Marcela' lettuce, the producer treatment showed the worst results. Finally for 'Lavínia' lettuce, the best harvesting system was represented by the treatments with root and producer cutting. Results of sensorial analysisindicated that from the sixth storage day lettuce plants were considered unacceptable in respect to its acquisition, except for the 'Lavínia' lettuce with root treatment and cut 2, which reach the same situationonly in the ninth day / Mestrado / Tecnologia Pós-Colheita / Mestre em Engenharia Agrícola

Made available in DSpace on 2014-08-20T14:22:05Z (GMT). No. of bitstreams: 1 Tese_ Elisane_ Schwartz.pdf: 2711774 bytes, checksum: 198da2f24d9d7d3d0515a50a0d4259b6 (MD5) Previous issue date: 2008-07-04 / The species of Arecaceae family show great economic importance. They are commercially explored for production of oils, starches, palm heart, waxes and fibers, as well as source of food. Butia capitata produces edible fruits with a good potential in pulp exploration, what can be natural consummated or processed as ice-cream, juice, liqueur and jellies. There has been little research on this specie, facing a large challenge of finding and improving the access with great potential economic. Therefore, this work aimed to evaluate the phenology and characters related to production and furthermore, the physic-chemical and functional attributes of the fruits of the different populations, seeking the best characteristics to commercial exploration. Experiments were carried out in the city of Santa Vitória do Palmar. The data used in the first article were taken from two seasons (2005/06 and 2006/07) and from three different populations of butia trees, by using six trees each and 50 fruits from each bunch produced. The second article was divided into two experiments. In the first one it was randomly selected ten butia tree genotypes and assessed characteristics of inflorescence. Therefore, each inflorescence was divided into basal, medium and apical region, and assessed eight rachillae of each region. In the second experiment, it was randomly selected six adult individuals of each of the four butia tree populations, what were regularly assessed for data collection during the two seasons. Data from the third article were collected by sampling fruits of the four populations, with six different genotypes in each population; it was verified the possible differences among populations and genotypes in each population. It was verified that populations of Butia capitata show variability for length of cycle, fruit epidermis color, juice volume, relationship between total soluble solids and total titratable acid, biometric characteristics of fruit and annual yield. One of the three assessed populations is pointed out in regard to annual yield and industrial income. Two of these populations show better biometric characteristics of the fruit. The other population shows best relationship between total soluble solids and total titratable acid. The flowering period of the butia tree occurs from November to March, reaching the peak in the first two weeks of January; and the harvest time from February to June, reaching the peak during March. One of the populations was late harvest. There are differences among genotypes considering the three inflorescence regions, for the characteristics of number of male and female flowers, relationship between male and female flowers and length of the rachillae. For most genotypes the basal part of the inflorescence is that shows the highest amount of female flowers. There is an average of 14.84 male flowers for each female flower. It was found an average value of 90.21% at studying the percentage of bunch that effectively achieved the maturation point. In each population there is genetic variability among the individuals for amount of total carotenoids and L-ascorbic acid. The average contents of ß- carotene and L-ascorbic acid in butia are 24.23μg. g-1 and 39.13mg.100g-1, respectively. / As espécies da família Arecaceae apresentam grande importância econômica e são exploradas comercialmente na produção de óleo, amido, palmito, ceras, fibras e como fonte de alimento. A espécie Butia capitata produz frutos comestíveis com potencial de exploração da polpa, que pode ser consumida ao natural ou na forma de sorvete, suco, licor e doce. Pouca pesquisa existe a respeito desta espécie, tornando-se um grande desafio encontrar e melhorar os acessos com potencial econômico. Nesse sentido, o objetivo deste trabalho foi avaliar a fenologia, caracteres relacionados à produção além de atributos físicos, químicos e funcionais dos frutos de distintas populações, com características viáveis para exploração comercial. Os experimentos foram conduzidos no município de Santa Vitória do Palmar. Os dados utilizados no primeiro artigo foram obtidos em duas safras, 2005/2006 e 2006/2007, em três populações distintas de butiazeiros, utilizando-se seis plantas de cada uma delas, com amostras de 50 frutos de cada cacho produzido. O segundo artigo foi dividido em dois experimentos, no primeiro, foram selecionados, ao acaso, dez genótipos de butiazeiro, sendo avaliadas características da inflorescência. Para isso, cada inflorescência foi dividida em três porções, basal, mediana e apical, sendo avaliadas oito ráquilas de cada região. No segundo experimento, foram selecionados, ao acaso, seis indivíduos adultos de cada uma das quatro populações de butiazeiros, que foram visitados regularmente para coleta de dados, durante duas safras. Os dados do terceiro artigo foram coletados através de amostras de frutos de quatro populações de butiazeiro, com seis genótipos distintos em cada população, sendo verificadas as possíveis diferenças entre as populações e entre os genótipos dentro de cada população. Foi verificado que as populações de Butia capitata avaliadas apresentam variabilidade para duração do ciclo, coloração da epiderme dos frutos, volume de suco produzido, relação entre sólidos solúveis totais e acidez total titulável, características biométricas de fruto e produtividade anual. Uma das três populações avaliadas se destaca em termos de produtividade e rendimento industrial. Duas dessas populações apresentam melhores características biométricas de fruto. Outra população apresenta a melhor relação entre sólidos solúveis totais e acidez total titulável. O período de floração do butiazeiro ocorre de novembro a março, sendo que o seu pico ocorre na primeira quinzena de janeiro e a colheita ocorre de fevereiro a junho, sendo o pico durante o mês de março, podendo também ser observado que uma das populações apresenta colheita mais tardia. Existem diferenças entre genótipos, considerando as três porções da inflorescência, para as características número de flores masculinas, números de flores femininas, relação entre flores masculinas e femininas e comprimento de ráquila. Para a maioria dos genótipos, a parte basal da inflorescência é a que apresenta a maior quantidade de flores femininas. Há uma relação média de 14,84 flores masculinas para cada flor feminina. Na avaliação do percentual de cachos que efetivamente atingiram ponto de maturação verificou-se um valor médio de 90,31%. Dentro de cada população, há variabilidade genética, entre os indivíduos, para o conteúdo de carotenóides totais e ácido L-ascórbico. Os conteúdos médios de ß- caroteno e ácido L-ascórbico, no butiá, são de 24,23μg.g-1 e 39,13mg.100g-1, respectivamente.

This study explored the development of a stationary robotic strawberry harvester that was combined with a movable bench system as part of the development of an industrially production system for a strawberry in a plant factory. At first the difficulty of approaching target fruit was investigated using table-top plants cultured in a greenhouse. Then the maximum force needed to separate fruit from the peduncle was measured. Based on these results, an end-effector was designed with three unique functions; (1) suction cup was vibrated to minimize the influence of the adjoining fruits at the time of approach; (2) compressed air was blown toward the adjoining fruits to force them away from the target fruit; (3) peduncle was removed with the motion of tilting and pulling the target fruit. Next, an optical system to equip the machine with the ability to detect and determine the position and coloration of strawberry fruit was constructed. The position of the fruit was detected from below with a stereo-camera. The coloration measurement unit was set against the bed of the movable bench system at fruit level to capture images of target fruit. Considering the spectral reflectance characteristics of strawberry fruit, the coloration measurement unit was equipped with red, green, and white LEDs. Finally the stationary robot was tested in an experimental harvesting system in which the robot was combined with a movable bench unit. In the experiment system, the stationary robot enabled highly stable harvesting operation. / Kyoto University (京都大学) / 0048 / 新制・論文博士 / 博士(農学) / 乙第12528号 / 論農博第2747号 / 新制||農||988(附属図書館) / 学位論文||H23||N4584(農学部図書室) / 28350 / (主査)教授 近藤 直, 教授 清水 浩, 准教授 飯田 訓久 / 学位規則第4条第2項該当

Large amounts of data in various forms are generated at a fast pace in today´s society. This is commonly referred to as “Big Data”. Making use of Big Data has been increasingly important for both business and in research. The forest industry is generating big amounts of data during the different processes of forest harvesting. In Sweden, forest infor-mation is sent to SDC, the information hub for the Swedish forest industry. In 2014, SDC received reports on 75.5 million m3fub from harvester and forwarder machines. These machines use a global stand-ard called StanForD 2010 for communication and to create reports about harvested stems. The arrival of scalable cloud technologies that com-bines Big Data with machine learning makes it interesting to develop an application to analyze the large amounts of data produced by the forest industry. In this study, a proof-of-concept has been implemented to be able to analyze harvest production reports from the StanForD 2010 standard. The system consist of a back-end and front-end application and is built using cloud technologies such as Apache Spark and Ha-doop. System tests have proven that the concept is able to successfully handle storage, processing and machine learning on gigabytes of HPR files. It is capable of extracting information from raw HPR data into datasets and support a machine learning pipeline with pre-processing and K-Means clustering. The proof-of-concept has provided a code base for further development of a system that could be used to find valuable knowledge for the forest industry.

Philosophiae Doctor - PhD / We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill™, Rovral™, Terminator™ and Teldor™ at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral™ significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit. / South Africa

Chez la banane dessert, les saveurs sucrée et acide, caractéristiques importantes pour les consommateurs, sont pilotées par les teneurs en acides citrique et malique. Ce travail a donc porté sur l’étude des processus physiologiques qui pilotent l’accumulation de ces acides dans la pulpe de banane (Musa sp. AA) en combinant analyse expérimentale et modélisation écophysiologique. Nous nous sommes notamment intéressés à l’effet du génotype et des conditions de croissance du fruit en adoptant une approche intégrative liant les phases pré et post récolte.Les effets de la charge en fruit, de la fertilisation potassique, et du stade de récolte sur l’accumulation du citrate et du malate dans la pulpe ont été étudiés expérimentalement. La variabilité génotypique a été prise en compte en choisissant trois génotypes présentant des acidités contrastées à maturité. Des différences d’évolution des teneurs en acides, dues à des modifications métaboliques, ont été observées entre les génotypes pendant les phases pré et post récolte. Le stade de récolte a eu un effet significatif sur les teneurs en acides des fruits pendant la maturation post récolte. La charge en fruit et la fertilisation potassique n’en ont eu aucun. Des modèles écophysiologiques ont été développés pour prédire différents critères d’acidité de la banane en pré et post récolte. Le pH et l’acidité titrable ont été prédits par un modèle d’équilibres acido-basiques, la teneur en malate par un modèle de stockage vacuolaire, et la teneur en citrate par un modèle du cycle de Krebs. Ces modèles ont permis d’identifier les processus physiologiques clés qui pilotent l’acidité de la banane. Des paramètres génotypiques ont été identifiés liés à l’activité de l’enzyme malique mitochondriale et à celle des transporteurs mitochondriaux du malate pour le modèle citrate, et à l’activité des pompes à protons vacuolaire ATPases pour le modèle malate. Ces modèles ont également permis de disséquer l’effet des conditions de croissance du fruit sur l’acidité de la banane. L’intégration des modèles développés dans un modèle d’élaboration de l’acidité et son utilisation potentielle pour l’amélioration variétale sont discutées. / Citric and malic acids determine the sourness and sweetness of banana pulp, which are the two main determinants of consumer preferences. The present work focused on the physiological processes controlling the accumulation of citric and malic acids in banana pulp (Musa sp. AA) using experimental analysis and ecophysiological modeling. We chose an integrative approach linking the pre and post-harvest stages, and focused on the effect of genotype and fruit growing conditions. Experiments were conducted to study the effect of fruit load, potassium fertilization and fruit age at harvest on the accumulation of citrate and malate in banana pulp. To account for genotypic variability, three genotypes with contrasting acidity at the eating stage were studied. Major differences in the pattern of citrate and malate accumulation were found in the three cultivars both during growth and post-harvest ripening and were shown to be the result of metabolic changes. The harvest stage had a significant effect on the concentrations of acids during post-harvest ripening. Fruit load and potassium fertilization had no effect.Ecophysiological models were developed to predict several banana acidity criteria during the pre and post harvest stages. pH and titratable acidity were predicted by a model of acid-base reactions; malate content by a model of vacuolar storage; and citrate content by a model of the TCA cycle. These models led to the identification of the key physiological processes that control banana acidity. Genotypic parameters were identified, which were related to the activity of the mitochondrial malic enzyme and of the malate mitochondrial carriers in the citrate model, as well as to the activity of the vacuolar proton pump, ATPase, in the malate model. The two models were also used to analyze the effects of fruit growth conditions on banana acidity.Combining the three models in a global model of banana acidity, and the possible use of this model for varietal improvement are discussed.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Rio Grande do Sul (RS), the most important state of grape production in Brazil, harvests, approximately, 780 thousand tons annually. One of the biggest constraint factors to the obtainment of higher production numbers is the incidence of late season diseases in vineyards, being botrytis bunch rot, caused by Botrytis cinerea, one of the major contributors for field and post-harvest losses. Red grapes can show more resistance against this fungus, due to higher levels of phenolic compounds. The use of biological control agents (BCAs) emerges as a promising alternative to control botrytis disease. For this reason, the objectives of this study were to test isolates from this fungal pathogen, originated from the two main grape production regions in the state of RS, trough in vitro direct confront test against BCAs fungal isolates (Trichoderma spp. and Gliocladium sp.) and to test the same pathogen isolates on semi in vivo biological control, against the BCAs isolates which obtained the highest biological activity during the in vitro test, on the post-harvest storage of table grapes, on a red and a white cultivar. The B. cinerea isolates used were UFSM SG01, UFSM SG02, from serra (mountain range) region, UFSM CM01, and UFSM CM02, from campanha meridional (meridional pampas) region. The BCAs isolates used in this study were Tricoderma spp., UFSM T20, UFSM T17, UFSM T15.1 (obtained from soil), UFSM TSG, UFSM TCM (obtained from the same grape bunches where B. cinerea was isolated, representing each region), and Gliocladium sp., UFSM G4DB (obtained from soil). UFSM TSG, UFSM TCM and UFSM T15.1 showed the highest biocontrol activity (B. A.) in vitro, in general over 50% against all B. cinerea isolates. The same BCAs were selected to be used at the semi in vivo test with detached berries for three inoculation periods: B+T, pathogen and BCA inoculated at the same time; B+24hT, pathogen inoculated first and BCA 24 h later, T+24hB, BCA inoculated first and pathogen 24 h later. A higher control, considered as the lower damage level, on T+24hB period, showed the importance of preventive treatment. Cracks on berries played a more important role than the color of the skin for botrytis infection. / O Rio Grande do Sul, o estado produtor de uvas mais importante no Brasil, colhe em média 780 mil toneladas por ano. Um dos maiores entraves para a obtenção de maiores médias de produção é a incidência de doenças de final de ciclo (DFC), sendo Botrytis cinerea, agente causador da podridão-cinzenta, um dos maiores responsáveis por perdas de produção no campo e na pós-colheita. Uvas tintas podem apresentar maior resistência à podridão-cinzenta, devido à maior concentração de compostos fenólicos. O uso de agentes de controle biológico (BCAs) é uma alternativa promissora no controle da podridão de botrytis. Dessa maneira, os objetivos deste estudo foram testar isolados do patógeno coletados das duas principais regiões vitivinícolas do RS em confronto direto in vitro com isolados de agentes antagonistas (Trichoderma spp e Gliocladium sp.) e testar os mesmos isolados do patógeno em controle biológico semi in vivo com os isolados antagonistas que obtiveram as maiores médias de atividade de biocontrole no teste in vitro, na pós-colheita de uvas de mesa, em cultivares branca e tinta. Os isolados de B. cinerea empregados foram UFSM SG01, UFSM SG02, UFSM SG 03, oriundos da serra, e UFSM CM01 e UFSM CM02, oriundos da campanha meridional. Os isolados antagonistas empregados no teste in vitro foram UFSM T20, UFSM T17, UFSM T15.1 (oriundos de solo), UFSM TSG, UFSM TCM (oriundos de cachos de uva coletados nas mesmas regiões de coleta do patógeno), de Trichoderma spp., e UFSM G4DB, de Gliocladium sp.. Os isolados UFSM TSG, UFSM TCM e UFSM T15.1 foram os três que obtiveram as maiores médias de atividade de biocontrole, em geral acima de 50%, para todos os isolados de B. cinerea, testados em confronto direto in vitro. Esses isolados BCAs foram selecionados para o teste de controle biológico semi in vivo em bagas destacadas, em três períodos de inoculação: B+T, antagonista e patógeno aplicados ao mesmo tempo; B+24hT, patógeno inoculado primeiro e antagonista 24h após, T+24hB, antagonista aplicado primeiro e patógeno 24h após. O maior controle, assumido a partir do menor grau de dano, no período T+24hB, evidenciou a importância do tratamento preventivo. Rachaduras em bagas tiveram maior influência do que a coloração da casca na ocorrência da podridãocinzenta.

Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Michael W. Sanderson / Shiga-toxin-producing Escherichia coli (STEC), of which enterohemorrhagic E. coli (EHEC) are a pathogenic sub-group, are foodborne pathogens of significant public health importance in the United States. STEC belong to the family Enterobacteriaceae commonly found in the large intestine of humans and other warm-blooded animals. EHEC harbors shiga toxin (stx1 and/or stx2) and eae genes which confers the ability to cause human illnesses. The U.S. Department of Agriculture Food Safety and Inspection Service declared seven STEC (O26, O45, O103, O111, O121, O145, and O157) as adulterants in ground beef and non-intact beef products to reduce/eliminate the burden of the pathogens in the beef production chain. STEC control efforts in the U.S. include the development of quantitative microbial risk assessment (QMRA) to identify mitigation strategies that are effective and economical in reducing exposure and reduce occurrence and public health risk from STEC in the beef chain. Collection of accurate and unbiased data is critical for the development of a QMRA that is valid for decision making. Determining the prevalence and concentration of the seven STEC in the different cattle types and seasons is valuable for the development a valid QMRA for STEC in beef production in the U.S. Our systematic review and meta-analysis study of the prevalence and concentration of E. coli O157 along the beef production chain indicated differences in the fecal prevalence of E. coli O157 among cattle types and seasons, revealed decreasing prevalence and concentration of E. coli O157 on cattle hides and carcass surfaces from pre-evisceration to the final chilled carcass stage, and identified study setting, detection method, hide or carcass swab area, and study design as significant sources of heterogeneity among studies reporting prevalence of E. coli O157 along the beef production chain. Bayesian estimation of the diagnostic performance of three laboratory methods (culture, conventional PCR [cPCR], and multiplex quantitative PCR [mqPCR]) used for the detection of the seven STEC in the feces of cattle is necessary to estimate true prevalence of EHEC in cattle. The analysis revealed highest sensitivity of mqPCR, followed by cPCR, and culture for the detection of E. coli O157; the cPCR and mqPCR had comparable specificity, but specificity of mqPCR method was heavily dependent on prior specification. The mqPCR method was the most sensitive for the detection O26, O45, and O103 serogroups. The cPCR method was more sensitive than the culture method for serogroups O26, and O121, but comparable for serogroups O45, O103, O111, and O145. The cPCR method showed higher specificity than mqPCR within serogroups O45, O121, and O145 but no apparent differences within serogroups O26, O103, and O111. A second order quantitative microbial risk assessment was developed to quantify the prevalence and concentration of the seven STEC on pre-evisceration beef carcasses and evaluate the impact of peri-harvest interventions. Simulation scenarios of current industry peri-harvest intervention practices showed variable effectiveness in reducing STEC contamination on pre-evisceration beef carcass, however, a scenario of increased adoption of peri-harvest interventions was more effective at reducing STEC contamination. Fecal-to-hide transfer and hide-to-carcass transfer had a large effect on prevalence and concentration of STEC on pre-evisceration carcasses.

Biogas production from energy crops grown on arable land often competes with food and feed production. Wetland plants offer an alternative source of biomass as well as offering a number of environmental benefits such as nutrient removal from wastewaters, carbon sequestration and reducing the use of mineral fertilizer. The aim of this study is to investigate the effect of harvest time on biogas production of Phragmites australis and Glyceria maxima and to perform a cost-benefit analysis of using these wetland plants as a substrate for biogas production. The results of the batch experiment show that the overall biogas production and specific methane yields of biomass harvested in June was higher than biomass harvested in September due the increased lignocellulosic nature of the more mature September plant. The cost-benefit showed that in Sweden it is not currently profitable to solely use wetland plants for biogas production. For both species the highest costs were seen in the June harvested biomass, this was due to the much higher fresh weight and increased transportation costs. For both species the highest revenues generated were the June harvested biomass, this was due to the higher specific methane yields. It was found that the harvest time that was closest to profitability from both species was the June harvest for Phragmites australis. Although the costs were higher for harvesting in June, this was outweighed by the higher amount of electricity produced for this scenario. If transportation distance was to be increased it could result in September being the favourable harvest time. Therefore, individual circumstances of the farmers could decide which is the optimal harvest time. Although solely using wetland plants for biogas production is not currently profitable, co-digestion and pre-treatment are options to investigate that could change this. Also if a greater financial value is put on the socioeconomic benefits such as increased biodiversity, aesthetic value and global warming mitigation it may be financially viable in the future.