Seventy strains of Bifidobacterium globosum isolated from gastrointestinal tracts of different animals were studied. Strains were grown at temperatures ranging from 25 to 46.5 degrees C in order to examine changes both in the expression of bifidobacterial outer proteins (BIFOPs) and in their hydrophobic properties. It was observed that the expression of BIFOPs found on the cell-surface changes according to growth temperature, with quantitative and/or qualitative variations. Generally speaking, it was observed that BIFOP expression at low-growth temperature was considerably attenuated, while at medium- and high-growth temperature it increased. Furthermore, at high-growth temperatures, the presence of a new common protein was detected in all the strains studied. Cells from B. globosum strains grown under different temperature conditions were studied in terms of their cellular hydrophobicity properties. At medium-growth temperature, the cell hydrophobicity was strictly correlated with BIFOP expression, while at low and high-growth temperatures, the presence of BIFOP only partially influenced the hydrophobic features.