Adesão de Pseudomonas fluorescens em superfícies utilizadas no processamento de alimentos
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2005-07-27
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Universidade Federal de Viçosa
Resumo
A adesão de Pseudomonas fluorescens ATCC 13525 foi avaliada pela microscopia de epifluorescência (EPF) e contagem padrão em placas (CPP) em superfícies usadas no processamento de alimentos nos tempos de contato 0, 2, 4, 6, 8 e 10 h. O aumento da adesão entre as superfícies, em razão do tempo, não foi acompanhado de forma similar pelas técnicas avaliadas. Por exemplo, no tempo quatro horas, as superfícies que apresentaram maiores logaritmos de UFC.cm-2 e que não apresentaram diferença significativa na adesão pelo teste de Scott-Knott (P > 0,05) foram poliuretano rugoso dupla face, silicone revestido com tecido, poli (cloreto de vinila) revestimento grosso com tecido, granito e mármore pela técnica EPF. Já pela técnica CPP, no mesmo tempo de contato, os maiores logaritmos de UFC.cm-2 foram para superfícies de silicone revestido com tecido, poliuretano rugoso dupla face, granito e poliuretano revestido com tecido. As superfícies de mármore, granito, poli (cloreto de vinila) revestimento grosso com tecido, poliuretano rugoso dupla face e silicone revestido com tecido diferiram das demais no grau de adesão, expresso em UFC.cm-2 (P < 0,05) nos tempos 4, 6, 8 e 10 horas, quando avaliadas pela técnica da epifluorescência, e de 2 e 10 horas, quando avaliadas pela contagem padrão em placas. Numa outra forma de avaliação, constatou-se também a diferença entre as 12 técnicas com relação ao agrupamento das superfícies de acordo com a similaridade de adesão. Assim, as superfícies que apresentaram maior percentagem de similaridade e maior média geral com relação à adesão pela técnica EPF foram mármore, granito e poliuretano rugoso dupla face. No caso da CPP, este mesmo fato foi constatado com as superfícies de poliuretano rugoso dupla face, silicone revestido com tecido e granito. As superfícies apresentaram características de microtopografias muito diferentes quando observadas por microscopia eletrônica de varredura, o que pode justificar as diferenças entre os graus de adesão observados. As técnicas possuem comportamentos diferentes para cada tempo de contato. Constatou-se que a CPP, além de fornecer resultados menores do que a EPF, também permite a detecção de valores de adesão mais baixos, sendo considerada uma técnica mais sensível. Porém, a CPP fornece resultados mais demorados do que a EPF. Para que haja detecção pela EPF, a quantidade de células aderidas aos cupons deve estar com contagens médias de uma célula por campo, no mínimo. A EPF permite verificar a morfologia das células, bem como, a distribuição destas bactérias aderidas às diferentes superfícies avaliadas. É recomendável utilizar a EPF para a quantificação de bactérias sésseis, principalmente quando as contagens sejam menores ou iguais a 4,1 x 105 UFC.cm-2. Este experimento mostrou que Pseudomonas fluorescens ATCC 13525 aderiu nas superfícies avaliadas. Entretanto, não há como sugerir a superfície mais recomendada para a utilização em processamento de alimentos devido a suas aplicações específicas. Os resultados mostram a importância de práticas higiênicas corretas na indústria de alimentos.
The adhesion of Pseudomonas fluorescens ATCC 13525 was evaluated by the epifluorescence microscopy (EPF) and the plate count method (CPP) to surfaces used in food processing at 0, 2, 4, 6, 8 and 10 h contact times. The adhesion increase among the surfaces, in relation to time, was not followed in a similar way by the evaluated techniques. For example, in four hours, the surfaces which showed greater CFU.cm-2 logarithms and that did not show a significant difference in the adhesion by the Scott- Knott test (P > 0.05) were the double-faced rugous polyurethane, silicon coated with cloth, PVC thick coated with cloth, granite and marble by the EPF technique. Whereas by the CPP technique, in the same contact time, the greater CFU.cm-2 logarithms were for the silicone coated with cloth, double-faced rugous polyurethane, granite and polyurethane coated with cloth surfaces. The marble, granite, PVC thick coated with cloth, double faced rugous polyurethane and silicone coated with cloth surfaces differed form the others in the adhesion degree expressed in CFU.cm-2 (P > 0.05) in the 4, 6, 8 and 10 h times, when evaluated by the epifluorescence technique and, at 2 and 10 h, when evaluated by the plate count method. In another kind of evaluation, the differences between the techniques concerning the surfaces cluster according to the adhesion similarity were also observed. Thus, the surfaces, which showed a greater similarity percentage and a greater general average concerning the adhesion by the 14 EPF technique, were marble, granite and double-faced rugous polyurethane. In the CPP, this same fact was observed with the double-faced rugous polyurethane, silicone coated with cloth and granite surfaces. The surfaces showed very different microtopography characteristics when observed by the scanning electron microscopy, which can justify the differences between the observed adhesion degrees. The techniques have different behaviors for each contact time. It was observed that CPP, besides providing results lower than the EPF, also allowed the detection of lower adhesion values, being considered a more sensitive technique. However, the CPP provides longer results than the EPF. So that there is a detection by EPF, the quantity of adhered cells to the coupons must be with, at least, an average count of one cell per field. The EPF allows the cell morphology assay as well as the distribution of these bacteria adhered to the different evaluated surfaces. It is recommendable to use the EPF technique for the sessile bacteria quantifying, especially when the count is lower or equal to 4,1 x 105 CFU.cm-2. This study showed that the Pseudomonas fluorescens ATCC 13525 adhered to the evaluated surfaces. However, there is no way to suggest the most recommendable surface for the use in the food processing due to their specific application. The results show the importance of the correct hygienic practices in the food industry.
The adhesion of Pseudomonas fluorescens ATCC 13525 was evaluated by the epifluorescence microscopy (EPF) and the plate count method (CPP) to surfaces used in food processing at 0, 2, 4, 6, 8 and 10 h contact times. The adhesion increase among the surfaces, in relation to time, was not followed in a similar way by the evaluated techniques. For example, in four hours, the surfaces which showed greater CFU.cm-2 logarithms and that did not show a significant difference in the adhesion by the Scott- Knott test (P > 0.05) were the double-faced rugous polyurethane, silicon coated with cloth, PVC thick coated with cloth, granite and marble by the EPF technique. Whereas by the CPP technique, in the same contact time, the greater CFU.cm-2 logarithms were for the silicone coated with cloth, double-faced rugous polyurethane, granite and polyurethane coated with cloth surfaces. The marble, granite, PVC thick coated with cloth, double faced rugous polyurethane and silicone coated with cloth surfaces differed form the others in the adhesion degree expressed in CFU.cm-2 (P > 0.05) in the 4, 6, 8 and 10 h times, when evaluated by the epifluorescence technique and, at 2 and 10 h, when evaluated by the plate count method. In another kind of evaluation, the differences between the techniques concerning the surfaces cluster according to the adhesion similarity were also observed. Thus, the surfaces, which showed a greater similarity percentage and a greater general average concerning the adhesion by the 14 EPF technique, were marble, granite and double-faced rugous polyurethane. In the CPP, this same fact was observed with the double-faced rugous polyurethane, silicone coated with cloth and granite surfaces. The surfaces showed very different microtopography characteristics when observed by the scanning electron microscopy, which can justify the differences between the observed adhesion degrees. The techniques have different behaviors for each contact time. It was observed that CPP, besides providing results lower than the EPF, also allowed the detection of lower adhesion values, being considered a more sensitive technique. However, the CPP provides longer results than the EPF. So that there is a detection by EPF, the quantity of adhered cells to the coupons must be with, at least, an average count of one cell per field. The EPF allows the cell morphology assay as well as the distribution of these bacteria adhered to the different evaluated surfaces. It is recommendable to use the EPF technique for the sessile bacteria quantifying, especially when the count is lower or equal to 4,1 x 105 CFU.cm-2. This study showed that the Pseudomonas fluorescens ATCC 13525 adhered to the evaluated surfaces. However, there is no way to suggest the most recommendable surface for the use in the food processing due to their specific application. The results show the importance of the correct hygienic practices in the food industry.
Descrição
Palavras-chave
Bactérias - Adesão, Pseudomonas fluorescens, Química de superfície, Alimentos - Preparo, Microscopia de epifluorescência, Contagem de placas I
Citação
CARELI, Roberta Torres. Adesão de Pseudomonas fluorescens em superfícies
utilizadas no processamento de alimentos. 2005. 65f. Dissertação (Mestrado em Ciência e Tecnologia de Alimentos) - Universidade Federal de Viçosa, Viçosa. 2005.