Adesão bacteriana em modelo de circuito de processamento de leite
Para entender melhor a adesão bacteriana em superfícies para processamento de alimentos, uma série de experimentos foi efetuada num modelo de linha de circulação de leite, equipado com cupons de prova em aço inoxidável, AISI 304, nas formas de T, cotovelo 90 o e cilíndrica. Avaliou-se, a adesão de E...
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Universidade Federal de Viçosa
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|Citação:||FIGUEIREDO, Hamilton Mendes. Adesão bacteriana em modelo de circuito de processamento de leite. 2000. 76 f. Tese (Doutorado em Ciência e Tecnologia de Alimentos) - Universidade Federal de Viçosa, Viçosa. 2000.|
|Resumo inglês:||With the objective of understanding the factors involved in the bacterial adhesion to the equipments for food processing were accomplished a series of experiments. In the evaluation of the capacity of adhesion of Enterococcus faecium, Pseudomonas aeruginosa ATCC 15442 and Bacillus cereus NCTC 11145 in spore and vegetative cells, before the circulation of the milk in the simulator, it was verified that the adhesion percentage, in stainless steel, for spore of Bacillus cereus was of 24.60%, while its spore more vegetative cells presents a value of 2.21%. The adhesion percentages for Pseudomonas aeruginosa and Enterococcus faecium were of 5.83% and 0.57%, respectively. With relationship to the adhesion after the circulation of the milk in the simulator was observed that the spore form and spore more vegetative cells of Bacillus cereus presented 4.10% and 2.3%, respectively, while for P. aeruginosa the found value was of 5.36% and for E. faecium the adhesion percentage was of 5.51%. When experiment was accomplished with the objective of evaluating the effect of the temperature of refrigeration of the milk in the bacterial adhesion, changes were observed in the adhesion percentages. P. aeruginosa, presented larger adhesion capacity for 18oC, before the circulation of the milk for the model, when compared with 10oC and 5oC. After the circulation of the milk the percentile of adhesion obtained for the different temperatures were plenty similar. With relationship to the influence of the velocity of circulation of the milk in the model, it was verified that at 0.5 m/s 10.7% of the cells was adhered in the cupon, while in the velocities of 1,0 m/s and 1.5 m/s the adhesion percentages were of 5.40 and 4.90, respectively. When the influence of the bacterial concentration was evaluated in relation to adhesion, was verified that larger concentrations of bacterias allow larger number of cells adhered to the coupons, even of the cells initially adhered most is removed by the circulation of the milk to 1 m/s, with that the percentages of final adhesion went of 5.36, 4,92 and 5.83, respectively for the bacterial 5 5 4 concentrations of 9.3x10 UFC/ml, 2.2x10 UFC/ml and 2.9x10 UFC/ml. The influence of the time of incubation of the milk about the adhesion showed that increasing the incubation period happens larger bacterial proliferation with consequent increase of the number of adhered bacterias, even so biofilme with high percentage of cells stuck as obtained it for the time of 48 hours (48.7%) they have a larger removal of cells for the flow of the milk when compared with the adhesions obtained for the times of 12 and 24 hours.|