AVALIAÇÃO MICROBIOLÓGICA DE BANANA CONSERVADA POR MÍNIMO DE PROCESSAMENTO E MÉTODOS COMBINADOS DA TECNOLOGIA DE OBSTÁCULOS

It has been evaluated the hurdle technology efficiency in banana conservation by combined methods, in relation to its microbiological aspect, when processed in situ at a low cost. Sucrose (30 °Brix syrup) was used as osmotic medium to reduce water activity. The syrup received an extra addition of 200 ppm SO2, 500 ppm sorbic acid, 600 ppm citric acid and 200 ppm calcium chloride. Before osmosis, fruits were steam-blanched at 100 ·C for two minutes, and after osmosis, they were packed in polyethylene bags, covered with syrup, sealed and heat-treated at 100°C for one minute. The process was followed up with microbiologic analysis of mesophilic aerobic bacterial, mold and yeast counting per gram. The most probable number (MPN) of feacal coliforms, for both fresh and blanched fruits, during osmosis and after heat-treatment were performed. A reduction of 98.8% was found in bacterial counts of mesophilic aerobic in comparison to the fresh fruit and after heat­-treatment (1.7x103 and 2.0x102 CFU/g respectively). The initial counting of mold and yeast (2.5 x101 CFU/g) and feacal coliforrns (<3/g) after heat-treatment were respectively reduced to <10 and <3. The results showed up the potentiality of hurdle technology conduced as aforementioned for in situ preservation of banana, related to its microbiological qualityAvaliou-se a tecnologia de conservação da banana (Musa balbisiana cal/a) por métodos combinados, quanto ao aspecto microbiológico, no processamento in situo Utilizou­se como meio asmático na redução da atividade de água, xarope de sacarose a 30 "Brix. Ao xarope adicionou-se 200 ppm de S02, 500 ppm de ácido sórbico, 600 ppm de ácido cítrico e 200 ppm de doreto de cálcio. Antes da osmose, os frutos foram branqueados em vapor a 100 ·C/2 minutos, e após a osmose acondicionados em sacos de polietileno, recobertos com xarope e tratados termicamente a 100 ·C/1 minuto. Realizou-se a avaliação do processo mediante determinações microbiológicas (contagens de bactérias aeróbias mesófilas, bolores e leveduras e Número Mais Provável (NMP) de coliformes fecais) no fruto in natura, branqueado, durante a osmose, após tratamento térmico e no armazenamento. Verificou­se redução de 98,82% na contagem de bactérias aeróbias mesófilas do fruto in natura (1,7x103 UFC/g), após o tratamento térmico (20 UFC/g). Os valores iniciais de bolores e leveduras (2,5x 102 UFC/g) e NMP de coliformes fecais ( < 3/g) no fruto in natura reduziram-se após o tratamento térmico, a valores de <10 UFC/g e