Table 1.
Acid tolerances of Lactobacillus fermentum strains at different pH at 0, 1, 2 and 3 h
| Cultures | Hours | Survivability of cultures in log CFU/ml (n = 2, mean ± SD) | ||||
|---|---|---|---|---|---|---|
| pH 6.5 | pH 3.5 | pH 3.0 | pH 2.5 | pH 2.0 | ||
| L. fermentum NCDC-400 | 0 | 9.20 ± 0.4 | 9.12 ± 0.3 | 8.98 ± 0.2 | 8.93 ± 0.4 | 8.67 ± 0.9 |
| 1 | 9.28 ± 0.5 | 8.94 ± 0.4 | 8.61 ± 0.2 | 7.58 ± 0.9 | 0 | |
| 2 | 9.51 ± 0.5 | 8.76 ± 0.5 | 8.54 ± 0.4 | 7.17 ± 0.6 | 0 | |
| 3 | 9.63 ± 0.3 | 9.79 ± 0.5 | 7.63 ± 0.3 | 7.54 ± 0.4 | 0 | |
| L. fermentum C-6 | 0 | 9.46 ± 0.2 | 9.14 ± 0.9 | 8.96 ± 0.3 | 8.75 ± 0.8 | 8.68 ± 0.1 |
| 1 | 9.51 ± 0.5 | 9.20 ± 0.8 | 8.65 ± 0.5 | 7.32 ± 0.2 | 0 | |
| 2 | 9.57 ± 0.8 | 9.17 ± 0.7 | 8.02 ± 0.7 | 7.67 ± 0.2 | 0 | |
| 3 | 9.79 ± 0.5 | 9.14 ± 0.3 | 8.08 ± 0.2 | 6.69 ± 0.1 | 0 | |
| L. fermentum C-9 | 0 | 9.38 ± 0.2 | 8.76 ± 0.5 | 8.62 ± 0.3 | 8.36 ± 0.1 | 8.32 ± 0.2 |
| 1 | 9.45 ± 0.4 | 7.95 ± 0.4 | 7.84 ± 0.5 | 6.95 ± 0.4 | 0 | |
| 2 | 9.45 ± 0.7 | 8.04 ± 0.1 | 7.99 ± 0.6 | 7.16 ± 0.4 | 0 | |
| 3 | 9.49 ± 0.1 | 8.23 ± 0.4 | 8.01 ± 0.7 | 7.13 ± 0.7 | 0 | |
| L. fermentum NCDC-156 | 0 | 8.76 ± 0.3 | 8.80 ± 0.9 | 8.53 ± 0.1 | 8.46 ± 0.2 | 8.71 ± 0.7 |
| 1 | 8.78 ± 0.8 | 8.89 ± 0.6 | 8.63 ± 0.3 | 8.39 ± 0.2 | 3.01 ± 0.8 | |
| 2 | 8.88 ± 0.5 | 8.90 ± 0.7 | 8.79 ± 0.9 | 8.40 ± 0.9 | 1.78 ± 0.1 | |
| 3 | 8.92 ± 0.9 | 8.91 ± 0.3 | 8.83 ± 0.2 | 7.37 ± 0.8 | 0 | |
| L. fermentum NCDC-605 | 0 | 9.41 ± 0.4 | 9.93 ± 0.2 | 9.20 ± 0.4 | 8.67 ± 0.2 | 8.60 ± 0.2 |
| 1 | 9.82 ± 0.9 | 9.11 ± 0.5 | 8.54 ± 0.4 | 8.14 ± 0.9 | 0 | |
| 2 | 9.94 ± 0.4 | 8.92 ± 0.9 | 8.46 ± 0.2 | 8.05 ± 0.3 | 0 | |
| 3 | 10.04 ± 0.1 | 8.74 ± 0.8 | 7.73 ± 0.2 | 7.59 ± 0.1 | 0 | |
| L. fermentum NCDC-606 | 0 | 8.53 ± 0.1 | 8.94 ± 0.4 | 8.88 ± 0.8 | 8.78 ± 0.8 | 8.76 ± 0.3 |
| 1 | 9.26 ± 0.5 | 7.68 ± 0.1 | 7.83 ± 0.8 | 7.62 ± 0.3 | 5.73 ± 0.3 | |
| 2 | 9.61 ± 0.2 | 7.51 ± 0.5 | 8.01 ± 0.5 | 7.64 ± 0.3 | 4.9 ± 0.8 | |
| 3 | 9.94 ± 0.9 | 7.59 ± 0.1 | 8.23 ± 0.4 | 7.74 ± 0.6 | 2.6 ± 0.2 | |
| L. fermentum MTCC-8711 | 0 | 8.98 ± 0.7 | 8.67 ± 0.2 | 8.81 ± 0.6 | 8.73 ± 0.2 | 8.55 ± 0.4 |
| 1 | 9.10 ± 0.3 | 8.22 ± 0.1 | 7.98 ± 0.2 | 7.05 ± 0.9 | 5.49 ± 0.1 | |
| 2 | 9.43 ± 0.8 | 8.23 ± 0.5 | 8.01 ± 0.8 | 7.4 ± 0.7 | 5.32 ± 0.2 | |
| 3 | 9.46 ± 0.2 | 8.28 ± 0.8 | 8.23 ± 0.4 | 7.60 ± 0.2 | 5.2 ± 0.4 | |
| L. fermentum KT-85 | 0 | 8.97 ± 0.3 | 8.79 ± 0.5 | 8.76 ± 0.3 | 8.53 ± 0.1 | 8.60 ± 0.2 |
| 1 | 9.26 ± 0.9 | 8.97 ± 0.8 | 8.80 ± 0.9 | 7.68 ± 0.1 | 5.53 ± 0.1 | |
| 2 | 9.68 ± 0.1 | 9.12 ± 0.7 | 8.88 ± 0.8 | 7.95 ± 0.9 | 4.45 ± 0.7 | |
| 3 | 9.44 ± 0.4 | 9.15 ± 0.2 | 8.94 ± 0.9 | 7.98 ± 0.2 | 3.79 ± 0.5 | |
| L. fermentum BIF-18 | 0 | 9.45 ± 0.1 | 9.25 ± 0.4 | 9.02 ± 0.1 | 8.99 ± 0.5 | 8.91 ± 0.9 |
| 1 | 9.93 ± 0.9 | 9.65 ± 0.3 | 9.14 ± 0.3 | 8.32 ± 0.2 | 3.47 ± 0.7 | |
| 2 | 10.24 ± 0.5 | 9.99 ± 0.2 | 9.04 ± 0.1 | 8.71 ± 0.6 | 0 | |
| 3 | 10.43 ± 0.1 | 10.04 ± 0.4 | 8.94 ± 0.4 | 8.63 ± 0.3 | 0 | |
| L. fermentum BIF-19 | 0 | 8.71 ± 0.7 | 9.27 ± 0.1 | 9.24 ± 0.5 | 9.15 ± 0.6 | 9.12 ± 0.3 |
| 1 | 10.15 ± 0.9 | 9.26 ± 0.7 | 9.24 ± 0.5 | 9.13 ± 0.3 | 3.58 ± 0.9 | |
| 2 | 10.19 ± 0.3 | 9.23 ± 0.4 | 9.21 ± 0.9 | 9.19 ± 0.3 | 0 | |
| 3 | 10.29 ± 0.5 | 9.22 ± 0.2 | 9.16 ± 0.5 | 9.16 ± 0.4 | 0 | |
| L. fermentum BIF-20 | 0 | 10.11 ± 0.3 | 9.18 ± 0.6 | 9.17 ± 0.2 | 9.15 ± 0.2 | 9.04 ± 0.1 |
| 1 | 10.16 ± 0.1 | 9.03 ± 0.9 | 8.85 ± 0.1 | 7.82 ± 0.6 | 0 | |
| 2 | 10.17 ± 0.2 | 9.24 ± 0.5 | 8.95 ± 0.9 | 8.34 ± 0.2 | 0 | |
| 3 | 10.24 ± 0.5 | 9.66 ± 0.2 | 8.77 ± 0.8 | 8.90 ± 0.3 | 0 | |
| L. rhamnosus GG | 0 | 10.19 ± 0.8 | 9.17 ± 0.3 | 9.12 ± 0.3 | 9.10 ± 0.3 | 8.96 ± 0.3 |
| 1 | 10.30 ± 0.7 | 9.83 ± 0.8 | 9.19 ± 0.3 | 8.76 ± 0.3 | 5.83 ± 0.8 | |
| 2 | 10.91 ± 0.3 | 10.29 ± 0.0 | 9.27 ± 0.1 | 8.80 ± 0.3 | 4.70 ± 0.5 | |
| 3 | 11.34 ± 0.4 | 10.03 ± 0.7 | 9.76 ± 0.3 | 9.70 ± 0.7 | 3.98 ± 0.6 | |
Presented values are means of triplicate determinations; ± indicates standard deviations from the mean