The viability of Bifidobacterium longum KCTC 3128, entrapped in calcium alginate beds in simulated gastroenteric juices (gastric and bile salt solution), was tested to evaluate the influences of several parameters (gel concentration, bead size, and initial cell number). The death rate of B. longum in beads after being sequentially exposed to simulated gastric juices and bile salt solution decreased propertionally with increasing both the alginate gel concentration and bead size. The number of initial cell loading in beads affected the numbers of survivors after being exposed to these solutions, while the death rate of the viable cells were not affected. From the results obtained, the influence of entrapment parameters on the survival of bifidobacteria was quantitatively and systematically evaluated by using a mathematical method.