MICROBIOLOGICAL EVALUATION OF BANANA CONSERVED BY THE MINIMUM LEVEL OF PROCESSING AND COMBINED METHODS OF HURDLE TECHNOLOGY

Abstract

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 quality