Table 2.
Survival Values for High- and Low-Pathogenic Salmonella Enteritidis Strains Exposed to Acidic (pH 2.6) and Oxidative (15 mM H2O2) Stress
| |
Number of survivors (mean log10 CFU±SE)a |
|||||
|---|---|---|---|---|---|---|
| |
Stress-resistant |
Stress-sensitive |
||||
| Conditions | UK | BC8 | G1 | C19 | G45 | C45 |
| pH 2.6 for 10 min (37°C) | 7.33±0.4 | 7.08±0.43 | 7.33±0.36 | 4.05±1.01b | 4.84±0.75b | 4.14±1.06b |
| pH 2.6 for 1 h (37°C) | 1.96±1.15 | 2.88±1.67 | 3.21±1.35 | <0.01b | 1.2±0.41b | 0.09±0.09b |
| pH 2.6 for 10 min (42°C) | 5.35±0.9 | 4.28±1.29 | 5.02±1.17 | 0.66±0.5b | 1.02±0.65b | 1.01±0.64b |
| pH 2.6 for 1 h (42°C) | 0 | 0 | 0 | 0 | 0 | 0 |
| 15 mM H2O2 for 10 min (37°C) | 8.07±0.04 | 8.07±0.06 | 8.06±0.05 | 6.1±0.18b | 5.53±0.19b | 6.33±0.19b |
| 15 mM H2O2 for 1 h (37°C) | 7.95±0.05 | 7.81±0.24 | 7.92±0.12 | 1.54±1.04b | 0.4±0.4b | 1.47±0.6b |
| 15 mM H2O2 for 10 min (42°C) | 8.06±0.08 | 8.08±0.1 | 8.06±0.07 | 6.4±0.23b | 5.33±0.19b | 6.5±0.07b |
| 15 mM H2O2 for 1 h (42°C) | 7.94±0.09 | 7.43±0.19 | 7.85±0.01 | 0 | 0 | 0 |
a
An initial 8 log colony forming units (CFU) of each strain was used in each stress-survival assay and the mean log10 CFU±standard error (SE) were calculated from three independent experiments.
b
For each stressor, means followed by asterisk indicate a significant difference from stress-resistant strains exposed to same stressor (p<0.05, Tukey's Kramer test).