The pH of the fermented milk inoculated which demonstrated that the phages of S. thermophilushad no effect on L. casei.
Overall, the co-cultures especially in the presence of phage
shortened the fermentation time.
For example, the pH value of LC fermented milk was 3.72 at 72 h. However,
the fermentation times reaching the same pH end point (3.72) in LC-ST and LC-ST-P fermented milk were only 61 h and 40 h, respectively (Fig. 1).
The acidification performance was promoted by L. casei co-cultured with phage-lysed
S. thermophilus, which provided a feasible and effective method to
improve probiotic fermentation.