TABLE 2.
D values of nonadapted and thymol-, carvacrol-, or trans-cinnamaldehyde-adapted Escherichia coli O157:H7 against thermal, acid, and hydrogen peroxide treatmentsa
| Treatment | D value (min)b |
|||
|---|---|---|---|---|
| Control | 1/2T | 1/2C | 1/2TC | |
| T (0.31 mg/ml) | 2.3 ± 0.3 A | 4.2 ± 0.1 B | 4.3 ± 0.6 B | 1.8 ± 0.4 A |
| C (0.31 mg/ml) | 0.9 ± 0.2 A | 4.5 ± 0.7 B | 5.1 ± 0.5 B | 0.8 ± 0.2 A |
| TC (0.63 mg/ml) | 77.1 ± 10.2 A | 161.7 ± 23.3 B | 160.7 ± 28.5 B | 243.7 ± 23.5 C |
| Thermal (58°C) | 1.5 ± 0.2 A | 2.4 ± 0.2 C | 2.4 ± 0.3 C | 1.9 ± 0.2 B |
| Acid (SGFc, pH 1.5) | 21.8 ± 2.3 A | 22.7 ± 1.6 A | 20.4 ± 3.1 A | 23.4 ± 1.1 A |
| Hydrogen peroxide (50 mM) | 4.1 ± 0.5 A | 5.4 ± 0.4 B | 5.5 ± 0.3 B | 5.1 ± 0.3 B |
a
Control, nonadapted; 1/2T, 0.16 mg/ml thymol; 1/2C, 0.16 mg/ml carvacrol; 1/2TC, 0.16 mg/ml trans-cinnamaldehyde.
b
Different uppercase letters in the same row represent statistically significant differences (P < 0.05) between control and adapted cells.
c
SGF, simulated gastric fluid.