The effect of acid adaptation conditions on heat resistance of Escherichia coli O157: H7
| dc.contributor.author | Tosun H. | |
| dc.contributor.author | Gönül Ş.A. | |
| dc.date.accessioned | 2025-04-10T11:17:12Z | |
| dc.date.available | 2025-04-10T11:17:12Z | |
| dc.date.issued | 2005 | |
| dc.description.abstract | The objective of this study was to determine the effect of acid adaptation conditions on heat resistance of E. coli O157: H7 932. E. coli O157: H7 was adapted to acid by exposing the cells to pH 4.5 (2h), pH 5.0 (1h), and pH 5.5 (1 h) in tryptic soy broth. D and z values of the acid adapted and control cultures at 54°C, 56°C, and 58°C were determined in E buffer. The heat resistance of E. coli O157: H7 increased significantly (p<0.05) after acid adaptation at pH 4.5 or pH 5.0. E. coli O157: H7 adapted to acid at pH 4.5 for 2 h had the highest D values at all temperatures tested (20.3-10.7-3.3 min) while D values of culture adapted to acid at pH 5.0 for 1 h were 18.2, 7.9, and 2.6 min at 54°C, 56°C and 58°C, respectively. Heat resistance of culture adapted to acid at pH 5.5 for 1 h and the control culture was not significantly different (P<0.05). Culture adapted to acid at pH 4.5 had the highest z value (5.10°C), whereas control culture had the lowest z value (4.33°C). This study showed that the magnitude of heat tolerance changed with the adaptation pH and at low adaptation pH, E. coli O157: H7 showed maximum heat resistance. Acid adaptation at pH 4.5 or 5.0 provides E. coli O157: H7 with cross-protection against heat treatments, and that this factor must be considered to estimate this pathogen's thermal tolerance accurately. | |
| dc.identifier.uri | http://hdl.handle.net/20.500.14701/52440 | |
| dc.title | The effect of acid adaptation conditions on heat resistance of Escherichia coli O157: H7 | |
| dc.type | Article |