RETENTION OF THE VIABILITY AND ANTAGONISTIC ACTIVITY BY SUBCULTURED BIFIDOBACTERIA

Retention of the viability of subcultured bifidobacteria is shown to d epend on the degree of neutralization of their acidic metabolic produc ts, storage temperature, maintenance medium, and strain. The highest r ate of survival was observed for neutral cultures (pH 7.0) stored at 4 degrees C. Bifidobacterium adolescentis strains MS-42 and GO-13 could well be stored in corn-lactose medium. The shelf life of B. adolescen tis GO-13 in liquid medium was 200 days at a survival rate of 1.7 x 10 (8) CFU/ml, and that of B. adolescentis GO-13 was 130 days at a surviv al rate of 3.9 x 10(8) CFU/ml. B. bifidum 791 and B, longum B379M coul d be maintained well in whey medium. The shelf life of the liquid cult ures of B. bifidum 791 and B, longum B379M was 160 days at survival ra tes of 5.0 x 10(7) and 1.0 x 10(7) CFU/ml, respectively. The antagonis tic activity of B, adolescentis MS-42, which was the strain most resis tant to subculturing, persisted for 60 days. After 160-day storage, th e antagonistic activity of this strain could be restored by six cultur e transfers in fresh corn-lactose medium.