In Canada, the control of relative humidity is a key issue in greenhouse production as it has a direct and significant effect on dehumidification cost, crop quality and yield. Experiments were carried out to measure plant transpiration rate and fruit yield under four different ambient water vapour pressure deficits. Four identical greenhouses were used to produce tomatoes (Lycopersicon esculentum Mill.) under four different regimes of water vapour pressure deficit (VPD). Dehumidification costs were highly correlated to VPD: low VPD produced low transpiration requiring little dehumidification. Thus, managing plant transpiration can lead to a more efficient use of transpiration for crop production. A model was developed to optimise greenhouse climatic conditions to maximize net profit. The present project validated this model, and compared measured values with those calculated from the transpiration and condensation sub-models and from the entire model itself. The sub-models and entire model proved to be accurate within 3% when used to simulate ideal climatic conditions for periods of one week or longer. Model sensitivity was greatest for exterior temperature because this factor affects heating costs without increasing yields. Using winter climatic conditions typical of Quebec City, Canada, three greenhouse climate control strategies were simulated and compared with respect to energy consumption and yield of a tomato crop. The merit and drawback of each strategy are discussed.

iv In recent years, outbreaks of infections associated with raw and minimally processed fruits and vegetables have been reported. Possible sources for contamination are irrigation water, manure, wash water, handling by workers and contact with contaminated surfaces. Pathogens can occur on raw and minimally processed produce at populations ranging from 103 to 109 CFU/g and able to survive and sometimes grow under various storage conditions. The objective of this study was to analyse the growth/survival of Salmonella Enteritidis at spot-inoculated or stem-injected cherry tomatoes during passive modified atmosphere packaging (MAP), controlled atmosphere (CA) and air storage at 7 and 22&deg / C. Low density polyethylene (LDPE) with a package size of 10x10 cm2 for 25&plusmn / 2 g tomatoes was used for MAP storage in which the gas composition equilibrated to 6% O2/ 4% CO2 and a carbon dioxide incubator was used for CA storage in which the CO2 level was monitored and maintained as 5% through the term of storage at 7 and 22&deg / C. During the research, the effect of ozone treatment (5-30 mg/L ozone gas for 0-20 min) was also considered for surface sanitation. The results demonstrate that S.Enteritidis can survive and/or grow during the storage of tomatoes depending on the location site of the pathogen on fruit, suspension cell density and storage temperature. During MAP, CA and air storage, S.Enteritidis with initial population of 7.0 log10 CFU/tomato survived on tomato surfaces with an approximate decrease of 4.0-5.0 log10 CFU/tomato in population within the storage period / however, in the case of initial population of 3.0 log10 CFU/tomato, cells died completely on day 4 during MAP storage and on day 6 during CA and air storage. The death rate of S.Enteritidis on the surfaces of tomatoes that were stored in MAP was faster than that of stored in air. Storage temperature was effective on the survival of S.Enteritidis for the samples stored at ambient atmosphere / cells died completely on day 6 at 7&deg / C and on day 8 at 22&deg / C. Stem scars provided protective environments for Salmonella / an approximate increase of 1.0 log10 CFU/tomato in stem-scar population was observed during MAP, CA and air storage at 22&deg / C within the period of 20 days. Cells survived with no significant change in number at 7&deg / C. The development of the microbial association in tomatoes was dominated by lactic acid bacteria (LAB). The pH values of the tomatoes changed approximately from 4.0 to 3.0 during the storage period. LAB grew well under all atmospheric conditions with or without the presence of S.Enteritidis. Gaseous ozone treatment has bactericidal effect on S.Enteritidis, inoculated on the surface of the tomatoes. 5 mg/L ozone gas treatment was not effective. 30 mg/L ozone gas treatment affected surface color.

Graduation date: 1936

Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references.

Mémoire (M.Sc.A.)--Université du Québec à Chicoutimi, 1990. / Document électronique également accessible en format PDF. CaQCU

Thesis (Ph. D.)--Auburn University. / Abstract. Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xi, 87 p. : ill. Vita. Includes abstract. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:28:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-20Bitstream added on 2014-06-13T18:35:02Z : No. of bitstreams: 1 silvajunior_taf_me_botfca.pdf: 480549 bytes, checksum: f7d5fb8db585125d630421fa598b3be8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Recentemente, em dois campos comerciais de tomateiro dos tipos Salada e Italiano, localizados respectivamente em Bragança Paulista e Mogi Guaçú, SP, foram observados sintomas de queima generalizada nas folhas. Em observações ao microscópio óptico de tecidos infectados foi constatada a presença de exsudação bacteriana. Isolamentos realizados em meio de cultura permitiram obter bactérias com formato bastonete, Gramnegativas, com colônias de coloração branca e produtoras de pigmento fluorescente em meio B de King. Isolados bacterianos foram submetidos a testes bioquímicos e fisiológicos, entre eles, LOPAT, sendo enquadrados no grupo III de LOPAT (- + - - +) e, portanto, identificados como sendo Pseudomonas cichorii. Esses resultados foram corroborados por testes serológicos de imunofluorescência indireta, com antissoros produzidos para isolado tipo de P. cichorii. Esta bactéria causa doença em várias culturas de importância econômica e ainda não havia sido constatada em nosso país, na cultura do tomateiro. Isolados bacterianos encontramse depositados na Coleção de Culturas de Fitobactérias do Instituto Biológico, sob os números de acesso IBSBF 2309 e IBSBF 2323. Foram desenvolvidos também estudos visando a determinação da gama de hospedeiras e a reação de 28 genótipos de tomateiro aos isolados de P. cichorii. Plantas de abobrinha, alface, beldroega, berinjela, beterraba, cenoura, couvebrócolo, datura, fumo, girassol, jiló, melão, pepino, petúnia, pimentão, rabanete, repolho, rúcula, salsa e tomateiro, no estágio de um par de folhas verdadeiras, foram inoculadas por pulverização com os isolados IBSBF 2309 e IBSBF 2323 e um isolado de P. cichorii de girassol (GIR-1). Os isolados IBSBF 2309 e IBSBF 2323 mostraram-se patogênicos à beldroega, à datura, ao girassol, ao pimentão e ao tomateiro, enquanto que o isolado de girassol foi... / Recently, generalized blight symptoms were observed in tomato leaves of the Salada and Italiano types, in two commercial fields located, respectively, in Bragança Paulista and Mogi Guaçú, SP, Brazil. The presence of bacterial exudation was verified in observations of infected tissues under the optical microscope. Rod-shaped, Gram-negative bacteria were obtained from isolations in culture medium; the colonies were white and produced fluorescent pigment in King's B medium. Bacterial isolates were submitted to biochemical and physiological tests, including LOPAT, and were classified into LOPAT group III (- + - - +); consequently, they were identified as Pseudomonas cichorii. These results were corroborated by indirect immunofluorescence tests, using antisera produced for the type isolate of P. cichorii. This bacterium causes diseases in several crops of economic importance and had not yet been observed in tomato in Brasil. Bacterial isolates were deposited in Phytobacteria Culture Collection of Instituto Biológico, under accession numbers IBSBF 2309 and IBSBF 2323. Studies were also carried out in order to determine the host range and reaction of 28 tomato genotypes to P. cichorii isolates. Caserta pumpkin, lettuce, purslane, eggplant, beet, broccoli, carrot, Jimson weed, sunflower, tobacco, scarlet eggplant, melon, cucumber, petunia, green pepper, radish, cabbage, arugula, parsley, and tomato plants, all with one pair of true leaves, were spray-inoculated with isolates IBSBF 2309 and IBSBF 2323 and one P. cichorii isolate from sunflower (GIR-1). Isolates IBSBF 2309 and IBSBF 2323 were pathogenic to purslane, Jimson weed, sunflower, green pepper, and tomatoe, while the sunflower isolate was only pathogenic to purslane, Jimson weed, and sunflower, but not to green pepper or... (Complete abstract click electronic access below)

Orientador: Ben-Hur Mattiuz / Banca: Ricardo Alfredo Kluge / Banca: Rogério Falleiros Carvalho / Banca: Antônio Carlos de Oliveira Ferraz / Banca: Teresinha de Jesus Deleo Rodrigues / Resumo: O objetivo deste trabalho foi avaliar o efeito da aplicação de pressões hiperbáricas na conservação pós-colheita de tomate de mesa cv. Débora. Os experimentos foram realizados no Laboratório de Tecnologia Pós-colheita da FCAV-UNESP, Câmpus de Jaboticabal, utilizando tomates provenientes de produções comerciais da região de Ribeirão Preto-SP. Na primeira etapa, os níveis de pressão hiperbárica aplicados foram 100 (controle), 200, 400, 600 e 800 kPa a temperatura de 23±1°C, durante 2, 4 ou 6 dias, e por mais 2 dias em condição de ambiente (23°C, 50% UR, 100 kPa). Na segunda etapa, os tratamentos consistiram em submeter os tomates às condições de pressão anteriormente descritas à temperatura de 13±1ºC, durante 4 ou 8 dias, e por mais 3 ou 6 dias em condição de ambiente (23°C, 88% UR, 100 kPa). Foram realizadas análises para avaliar a qualidade pós-colheita (perda de massa, firmeza, coloração da casca, teor de sólidos solúveis, acidez titulável, taxa respiratória e produção de etileno) e a influencia no sistema antioxidante dos tomates (teor de licopeno, ácido ascórbico, atividade antioxidante total, polifenóis, peroxidacão de lipídeos e atividade das enzimas superóxido dismutase (SOD), catalase (CAT) e peroxidase (POD). A pressão de 800 kPa a 23°C diminuiu a perda de massa em 82% depois de 6 dias. A mesma tendência foi observada para a firmeza, sendo que no 6º dia de armazenamento, os frutos com maior firmeza foram aqueles submetidos às pressões de 600 e 800 kPa (média de 17,60 ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this work was to evaluate the effect of the application of hyperbaric pressures on the post-harvest conservation of table tomato cv. Debora. The experiments were carried out at the Laboratory of Post-Harvest Technology of FCAV-UNESP, Jaboticabal Campus, using tomatoes from commercial production in the region of Ribeirão Preto-SP. In the first stage, the applied hyperbaric pressure levels were 100 (control), 200, 400, 600 and 800 kPa at 23±1°C for 2, 4 or 6 days and for a further 2 days in ambient conditions (23°C, 50% RH, 100 kPa). In the second stage, the treatments consisted in subjecting the tomatoes to the pressure conditions described above at 13±1°C for 4 or 8 days and for another 3 or 6 days under ambient conditions (23°C, 88% RH, 100 kPa). Analysis were carried out to evaluate the post-harvest quality (loss of mass, firmness, peel color, soluble solids content, titratable acidity, respiratory rate and ethylene production) and the influence on the antioxidant system of the tomatoes (lycopene content, ascorbic acid content, total antioxidant activity, polyphenols, lipid peroxidation and activity of the enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD). The pressure of 800 kPa at 23°C decreased the mass loss by 82% after 6 days. The same trend was observed for firmness, and on the 6th day of storage, the fruits with the greatest firmness were those submitted to pressures of 600 and 800 kPa (mean of 17.60 N), while the tomatoes of th... (Complete abstract click electronic access below) / Doutor