The objective of the study was to determine the survivability of an Lactobacillus casei KNE-1 probiotic strain in the banana-milk drink (3:2), stored at a temperature of 10°C for 32 days, depending on the added prebiotics: oligofructose (0.5%) and inulin with sucrose (totally 0.5%). For the purpose of this study, during of the period of storing the drink, changes in its pH value were also measured. The scope of the study included: preparing the drink; inoculating it by the L. casei KNE-1 probiotic strain; accomplishing a fermentation process at a temperature of 37°C for 12 hours; examining the survivability of the strain used; and determining the pH-value of the drink during its storing. Microbiological examinations were conducted using a pour plate method on an MRS agar manufactured by a ‘BIOCAR DIAGNOSTICS’ Company (the incubation conditions: temperature: 37°C; duration: 48 hrs). It was found that while the banana-milk drink fermented, the count of Lactobacillus casei KNE-1 bacteria in the drink increased by 3 logarithmic orders in the drink with oligofructose added, and by 7 logarithmic orders in the drink with inulin and sucrose added. And during storing, the cell count of the examined strain increased by 4 logarithmic orders in the drink with oligofructose added, whereas the cell count of this strain decreased by 1 logarithmic order in the drink with the addition of inulin. During the period when two fermented drinks were stored, their pH-values significantly decreased (from 5.41 to 3.93 in the drink with inulin and sucrose, and from 5.43 to 3.83 in the drink with oligofructose), and this decrease resulted in the decrease of their sensory quality.
fermented milk drink, probiotics, survivability, prebiotics, inulin, oligofructose