Effect of production conditions on the stability of a human bifidobacterial species Bifidobacterium longum in yogurt.
OBJECTIVE
Human bifidobacteria are more sensitive to external environmental factors than animal bifidobacteria, and it is difficult to ensure their stable survival in yogurt. The purpose of this investigation was to observe the survival of human bifidobacteria in yogurts produced under various production conditions.


METHODS
Frozen or lyophilized bifidobacteria starters containing Bifidobacterium longum BB536 originally isolated from an infant, and commercial lyophilized yogurt starters were used for yogurt preparation. After producing yogurts under various conditions, the survival of bifidobacteria in these yogurts over various storage periods was observed.


RESULTS
Although there were some differences in bifidobacterial survival in yogurt between various production conditions, more than 1.0 x 10(7) CFU g(-1) of Bif. longum survived in yogurt after 35 days' storage at 5 degrees C. Lower fermentation temperature (37 degrees C) and inclusion of Lactococcus lactis in the starter significantly (P < 0.05) improved survival of Bif. longum in the yogurt.


CONCLUSIONS
In this investigation, the human bifidobacterial strain Bif. longum survived adequately in yogurt, although the fermentation temperature and starter composition affect bifidobacterial survival.


CONCLUSIONS
This investigation indicates that stable probiotic yogurt using human bifidobacteria can be produced by choosing optimal production conditions.
Abe
F
F
Food Science & Technology Institute, Morinaga Milk Industry Co., Ltd., Kanagawa Prefecture, Japan. f_abe@morinagamilk.co.jp
Tomita
S
S
Yaeshima
T
T
Iwatsuki
K
K
D001644:Bifidobacterium / Q000254:growth & development* / Q000302:isolation & purification; D015169:Colony Count, Microbial; D005285:Fermentation; D005516:Food Microbiology; D006801:Humans; D013294:Lactococcus lactis; D019936:Probiotics; D013696:Temperature; D015014:Yogurt / Q000382:microbiology*