FIG 6.

Comparison of CF-efflux activity, esterase activity, membrane integrity, and colony-forming activity. LcS-milk samples stored at 4°C for different periods were used for analysis. Day −14 means the day of production of LcS-milk, and day 0 means the best-before date of the product. The rates of CF-efflux positive (CF⁻PI⁻ in the presence of glucose), membrane-integrity positive (PI⁻), esterase-activity positive (CF⁺ in the absence of glucose), and colony-formation were compared. The colony-formation rate was determined by single-cell sorting of L8⁺ cells into MRS agar by using a cell sorter and by calculating the percentage of colony-forming cells.