TABLE 1.
Effect of cell status and final product pH on the thermotolerance at 55, 58, 60, and 62°C of E. coli O157:H7, heated in pepperoni pre- and postfermentation
| Heating temp (°C) | Cell status | D value (min)a
|
Least-significant difference (7 df)b | |||
|---|---|---|---|---|---|---|
| Final product pH of 4.8 (standard)
|
Final product pH of 4.5 (low)
|
|||||
| Prefermentation | Postfermentation | Prefermentation | Postfermentation | |||
| 55 | Acid adapted | 35.09 (7.87) | 22.10 (0.72) | 39.25 (12.10) | 17.62 (5.06) | |
| Non-acid adapted | 39.52 (10.03) | 62.02 (16.09) | 46.21 (1.75) | 16.01 (2.89) | 14.05 | |
| 58 | Acid adapted | 10.97 (1.43) | 5.22 (0.71) | 14.81 (2.68) | 4.51 (1.34) | |
| Non-acid adapted | 17.21 (2.08) | 14.35 (2.31) | 18.39 (1.47) | 4.10 (0.63) | 2.77 | |
| 60 | Acid adapted | 3.62 (0.19) | 4.37 (1.44) | 5.36 (0.47) | 2.90 (0.56) | |
| Non-acid adapted | 5.87 (0.78) | 6.12 (0.82) | 6.73 (1.11) | 2.35 (0.45) | 1.39 | |
| 62 | Acid adapted | 1.33 (0.22) | 1.64 (0.25) | 1.89 (0.05) | 1.25 (0.15) | |
| Non-acid adapted | 2.30 (0.41) | 2.53 (0.24) | 2.48 (0.47) | 1.16 (0.21) | 0.52 | |
a
Standard deviations are in parentheses.
b
95% confidence limit.