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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.
1

AvaliaÃÃo microbiolÃgica e parasitolÃgica nos processos de higienizaÃÃo de alfaces (Lactuca sativa L.) de diferentes cultivos / Microbiology and Parasitology evaluation process of sanitization Lettuce (Lactuca sativa L.) of different cultivars

Eveline de Alencar Costa 30 June 2011 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A sanidade das hortaliÃas que sÃo consumidas cruas à fator relevante à saÃde devendo ser garantida mediante a sanitizaÃÃo com produtos quÃmicos que tenham aÃÃo eficaz na eliminaÃÃo, reduÃÃo e/ou remoÃÃo dos contaminantes presentes. A forma tradicional de higienizaÃÃo de vegetais compreende a lavagem com Ãgua corrente seguida de imersÃo em soluÃÃo de cloro a 200ppm e enxÃgÃe para remover as sujidades remanescentes e resÃduos do produto quÃmico. No entanto, alguns estudos apontam que esta sanitizaÃÃo nÃo garante a inocuidade das hortaliÃas, pois embora reduza a carga microbiana, nÃo à eficiente na eliminaÃÃo de algumas formas parasitÃrias. Diante disso, a presente pesquisa objetivou detectar microrganismos, protozoÃrios, helmintos e artrÃpodes em alfaces (Lactuca sativa, L.), variedade crespa, provenientes de cultivo convencional, orgÃnico e hidropÃnico, na sua forma in natura e apÃs dois mÃtodos de higienizaÃÃo: teste (aplicaÃÃo do detergente e soluÃÃo clorada a 200ppm) e tradicional (uso apenas da soluÃÃo clorada a 200ppm). Todas as alfaces estavam contaminadas por coliformes fecais, porÃm as amostras orgÃnicas e hidropÃnicas apresentaram valores mÃdios dentro do padrÃo estipulado pela legislaÃÃo, (21Â74NMP/g e 24Â40 NMP/g, respectivamente) ao contrÃrio das convencionais (152Â286NMP/g). Em 100% das amostras de alfaces convencionais e orgÃnicas nÃo apresentaram contaminaÃÃo por Salmonella sp., mas 20% das amostras hidropÃnicas estavam contaminadas por esse patÃgeno, sendo classificadas como imprÃprias para consumo. Nas anÃlises parasitolÃgicas foram detectados organismos potencialmente patogÃnicos para o homem: cistos Giardia sp. (2), ovos de Ascaris sp. (6) e ovo de Taenia sp. (1), com seis ocorrÃncias em alfaces convencionais e trÃs em orgÃnicas. Foram ainda detectados cistos de ameba e larvas de nematÃdeos morfologicamente anÃlogos aos que se encontra no homem, porÃm mais provavelmente eram formas de vida livre provenientes da terra. Foram observadas em abundÃncia formas de vida livre entre os protozoÃrios, os helmintos nematÃdeos, e os artrÃpodes (estes com destaque nas alfaces hidropÃnicas) veiculados nas sujidades das alfaces, refletindo a composiÃÃo dos ambientes de cultivo. Avaliando os dois processos de sanitizaÃÃo estudados constatou-se que a mÃdia dos valores de coliforme fecal nos diferentes tipos de alfaces foi menor no mÃtodo teste do que no tradicional, evidenciando maior eficiÃncia. A etapa da prÃ-lavagem reduziu em 60% a contaminaÃÃo inicial de coliformes fecais; a lavagem com detergente foi eficaz quando comparada com a reduÃÃo obtida na etapa seguinte. O mÃtodo tradicional promoveu diminuiÃÃo significativa na contaminaÃÃo inicial de coliformes fecais, no entanto, nÃo houve diferenÃa significativa quando comparada com o mÃtodo teste nem com a etapa da lavagem com detergente isoladamente, comprovando mais uma vez a eficÃcia deste Ãltimo. Para a remoÃÃo das formas de helmintos, protozoÃrios e artrÃpodes em geral, ambos os mÃtodos foram eficientes, sem apresentarem diferenÃa significativa. Quando foram analisadas separadamente as diferentes etapas dos procedimentos de higienizaÃÃo, constatou-se que houve significÃncia estatÃstica para a remoÃÃo de helmintos, com melhor eficiÃncia do procedimento teste, podendo-se sugerir que a higienizaÃÃo realizada apenas com detergente alcanÃaria os mesmos resultados de detergente e cloro. Deste modo, concluÃmos que a higienizaÃÃo teste, tanto para a remoÃÃo de helmintos como para a reduÃÃo de coliformes fecais, apresentou maior eficÃcia. / The vegetables sanity that are eaten raw is a relevant factor to health must be ensured by sanitizing with chemicals that have effective action to eliminate, reduce and / or removal of contaminants. The traditional way of cleaning includes washing vegetables under running water followed by immersion in 200ppm chlorine solution and rinse to remove dirt and remnants of the chemical waste. However, some studies indicate that this sanitization does not guarantee the safety of vegetables, for though while reduces the microbial load, it is not efficient in the elimination of some parasitic forms. Therefore, this study aimed to detect microorganisms, protozoa, helminths and arthropods in lettuce (Lactuca sativa L.), curly variety, from conventional farming, organic and hydroponic, in its fresh form and after two methods of cleaning: test (application of detergent and chlorine solution to 200ppm) and traditional (use of only a 200ppm chlorine solution). All lettuce were contaminated by fecal coliforms, but the hydroponic and organic samples had mean values within the standard stipulated by law, 21Â74NMP/g and 24Â40 NMP/g, respectively) unlike the conventional (152  286NMP/g). In 100% of the samples of conventional and organic lettuces were not contaminated with Salmonella sp. but 20% of hydroponic samples were contaminated by this pathogen, being classified as unfit for consumption. In parasitological analyses were detected in organisms potentially pathogenic to humans: Giardia sp cysts. (2), eggs of Ascaris sp. (6) and eggs of Taenia sp. (1), with six occurrence in three lettuces in conventional and organic. Giardia sp cysts. (2), eggs of Ascaris sp. (6) and eggs of Taenia sp. (1), with six occurrence in three lettuces in conventional and organic. Yet been detected amoeba cysts and larvae of nematodes morphologically similar to those found in man, but more likely were forms of life free from the earth. Forms were observed in abundance among free-living protozoa, nematodes, helminths, and arthropods (especially those in hydroponic lettuce) served in lettuce dirt, reflecting the composition of culture environments. Evaluating the two processes of sanitization studied it was found that the mean of fecal coliform in the different types of lettuce was lower in the test method than the traditional, with increased efficiency. The stage of pre-washing reduced by 60% the initial contamination of fecal coliform, the detergent wash was effective when compared with the reduction achieved in the next step. The traditional method promoted significant decrease in the initial contamination of fecal coliform bacteria, however, no significant difference when compared with the test method or with the step of washing with detergent alone, proving once again its effectiveness. For removal of the forms of helminths, protozoa and arthropods in general, both methods were effective, showing no significant difference. When analyzed separately the different stages of cleaning procedures, it was found that there were significant for the removal of helminths, with better efficiency of the testing procedure, which may suggest that the cleaning with detergent performed only achieve the same results of detergent and chlorine. Thus, we conclude that test hygienization, both for the removal of helminths as to reduce fecal coliform bacteria, showed greater efficacy.

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