Optimization of heat and relative humidity conditions to reduce Escherichia coli O157: H7 contamination and maximize the germination of radish seeds

M. K. Song, H. W. Kim, Min-Suk Rhee

Research output: Contribution to journalArticle

9 Citations (Scopus)

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 languageEnglish
Pages (from-to)14-20
Number of pages7
JournalFood Microbiology
Volume56
DOIs
Publication statusPublished - 2016 Jun 1

Keywords

  • Desirability function
  • Heat and relative humidity
  • Optimization
  • Response surface methodology
  • Seed decontamination

ASJC Scopus subject areas

  • Food Science
  • Microbiology

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