Table 1.
Reduction of E. coli O157:H7 populations after various ultrasound treatments for different power intensity and treatment time.
| Time (min) | Ultrasonic intensity |
|||
|---|---|---|---|---|
| 64 W/cm2 | 191 W/cm2 | 382 W/cm2 | 573 W/cm2 | |
| 3 min | 0.24 ± 0.02Fc | 0.26 ± 0.00Fb | 0.40 ± 0.02Fb | 0.51 ± 0.02Ia |
| 6 min | 0.38 ± 0.09Ec | 0.58 ± 0.04Eb | 0.66 ± 0.06Eb | 0.87 ± 0.07Ha |
| 9 min | 0.76 ± 0.09Db | 0.82 ± 0.01Db | 0.81 ± 0.04Eb | 1.15 ± 0.01Ga |
| 12 min | 1.09 ± 0.02Cc | 1.10 ± 0.01Cc | 1.36 ± 0.12Db | 2.15 ± 0.03Fa |
| 15 min | 1.29 ± 0.09Bc | 1.40 ± 0.07Bc | 1.94 ± 0.05Cb | 2.26 ± 0.05Ea |
| 18 min | 1.38 ± 0.06Bd | 1.59 ± 0.10Ac | 1.96 ± 0.05Cb | 2.50 ± 0.03Da |
| 21 min | 1.51 ± 0.04Ac | 1.61 ± 0.01Ac | 2.59 ± 0.09Bb | 3.05 ± 0.04Ca |
| 24 min | 1.53 ± 0.07Ac | 1.60 ± 0.05Ac | 2.69 ± 0.07Bb | 3.27 ± 0.10Ba |
| 27 min | 1.54 ± 0.11Ac | 1.66 ± 0.01Ac | 3.13 ± 0.12Ab | 3.52 ± 0.19Aa |
Note: Initial bacterial population was approximately 8.93 ± 0.11 log CFU/mL.
Values are the mean of triplicate measurements ± standard deviation; values with different lowercase letters in the same row and uppercase letters in the same column showed a significant difference at P < 0.05.