Effects of culture conditions on the subsequent heat inactivation of E. coli O157:H7 in apple juice |
| |
| Authors: | Alonzo A Gabriel Hiroyuki Nakano |
| |
| Affiliation: | 1. Food Science & Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 4, Singapore 117543, Singapore;2. National University of Singapore (Suzhou) Research Institute, No. 377 Linquan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China;3. Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Singapore;4. Department of Food Science and Biotechnology, Kyungnam University, Changwon 631-701, Republic of Korea |
| |
| Abstract: | Escherichia coli O157:H7 cells were grown in various acidic growth media including an acidogenic nutrient broth (NB) supplemented with 1% glucose (NBG) and NB acidified to pH 4.5 with 0.25% citric or malic acids. The pH in NBG continuously decreased, reaching a final pH of 4.46 after 28 h. The pH in the control culture (NB) did not significantly change throughout the incubation. When heated in apple juice at 55 °C, cells grown in NBG had the significantly highest D55 value (250 ± 39.67 s). Thermal inactivation rates established for cells grown in NB, citric acid- and malic acid-acidified NBs were 51.39 ± 1.34, 25.46 ± 1.21, and 45.42 ± 0.36 s, respectively. When compared with the D55 values of cells previously exposed to combinations of environmental stress factors, cells grown in NBG were also found to be significantly heat resistant and were deemed appropriate to be used in heat challenge studies. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
