Abstract
We previously reported that a combination of heat and relative humidity (RH) had a marked bactericidal effect on Escherichia coli O157:H7 on radish seeds. Here, response surface methodology with a Box-Behnken design was used to build a model to predict reductions in E. coli O157:H7 populations based on three independent variables: heating temperature (55 °C, 60 °C, or 65 °C), RH (40%, 60%, and 80%), and holding time (8, 15, or 22 h). Optimum treatment conditions were selected using a desirability function. The predictive model for microbial reduction had a high regression coefficient (R2 = 0.97), and the accuracy of the model was verified using validation data (R2 = 0.95). Among the three variables examined, heating temperature (P < 0.0001) and RH (P = 0.004) were the most significant in terms of bacterial reduction and seed germination, respectively. The optimum conditions for microbial reduction (6.6 log reduction) determined by ridge analysis were as follows: 64.5 °C and 63.2% RH for 17.7 h. However, when both microbial reduction and germination rate were taken into consideration, the desirability function yielded optimal conditions of 65 °C and 40% RH for 8 h (6.6 log reduction in the bacterial population; 94.4% of seeds germinated). This study provides comprehensive data that improve our understanding of the effects of heating temperature, RH, and holding time on the E. coli O157:H7 population on radish seeds. Radish seeds can be exposed to these conditions before sprouting, which greatly increases the microbiological safety of the products.
Original language | English |
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Pages (from-to) | 14-20 |
Number of pages | 7 |
Journal | Food Microbiology |
Volume | 56 |
DOIs | |
Publication status | Published - 2016 Jun 1 |
Bibliographical note
Funding Information:This study was supported by a Korea University grant ( K1506801 ). The authors thank the Institute of Biomedical Science and Food Safety , KU-CJ Food Safety Hall, for providing equipment and facilities.
Publisher Copyright:
© 2015 Elsevier Ltd.
Keywords
- Desirability function
- Heat and relative humidity
- Optimization
- Response surface methodology
- Seed decontamination
ASJC Scopus subject areas
- Food Science
- Microbiology