Effects of mutual cultivation of <i>Bifidobacterium longum</i>
B 379 M and <i>Lactococcus lac-tis ssp. cremoris </i>on accumulation of the extracellular metabolites have been studied. Combination of the cultures at the ratio 80:20 is characterized by higher antagonistic activity, synthetizes higher levels of exopolysacchrides and antimutagen substances than monocultures.