Combined effects of chlorine dioxide, drying, and dry heat treatments in inactivating microorganisms on radish seeds

Jihyun Bang, Haeyoung Kim, Hoikyung Kim, Larry R. Beuchat, Jee Hoon Ryu

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

We determined the combined effectiveness of ClO2 (200 and 500 μg/ml, 5 min), air drying [25 °C, 40% relative humidity (RH), 2 h], and mild dry heat (55 °C, 23% RH, up to 48 h) treatments in killing total aerobic bacteria (TAB), Escherichia coli O157:H7, and molds and yeasts (MY) on radish seeds. A 5.1-log reduction in the number of TAB was achieved on radish seeds treated with 200 or 500 μg/ml ClO2 followed by air drying for 2 h and dry heat treatment for 48 h or 24 h, respectively. When radish seeds were treated with 200 and 500 μg/ml ClO2, air dried, and heat treated for 12 h and 6 h, respectively, the initial population of E. coli O157:H7 (5.6 log CFU/g) on seeds was reduced to an undetectable level (<0.8 log CFU/g). However, the pathogen was detected in 5-day-old sprouts. The reduction of MY (1.2-1.0 log CFU/g) on radish seeds under similar experimental conditions was not changed significantly during subsequent heat treatment up to 48 h. Results show that treating radish seeds with 500 μg/ml ClO2, followed by air dried at 25 °C for 2 h and heat treatment at 55 °C for 36 h achieved a >5-log CFU/g reduction of TAB and E. coli O157:H7. These observations will be useful when developing effective strategies and practices to enhance the microbiological safety of radish sprouts.

Original languageEnglish
Pages (from-to)114-118
Number of pages5
JournalFood Microbiology
Volume28
Issue number1
DOIs
Publication statusPublished - 2011 Feb

Keywords

  • Chlorine dioxide
  • Dryheat treatment
  • Drying
  • Escherichia coli O157:H7
  • Radish seed

ASJC Scopus subject areas

  • Food Science
  • Microbiology

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