Inactivation of Bacillus subtilis spores at various germination and outgrowth stages using intense pulsed light

Hye Lim Jo, Hee Jeong Hwang, Myong Soo Chung

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19 Scopus citations


It is important to inactivate spore-forming bacteria in foods because their spores are highly resistant to various stresses. Although thermal treatment is an effective inactivation method, the associated high temperatures can cause changes in food quality. Intense pulsed light (IPL) is a nonthermal technique that can effectively improve food safety. This study evaluated the inactivation effects of IPL at various fluences on Bacillus subtilis spores. IPL treatment at a total fluence of 7.40 J/cm 2 resulted in a 7 log reduction, indicating the potential of IPL to effectively inactivate bacterial spores. The sensitivity of B. subtilis spores to IPL during germination and outgrowth was also measured. The resistance to the IPL increased temporarily until 1 h after the start of incubation, and then gradually decreased for longer incubation periods. This temporary increase in resistance at the early stage of incubation was attributed to the leakage of dipicolinic acid from the spores. The results also showed that the inactivation efficiency increases after 1 h pre-incubation because the numbers of vegetative cells increased with the incubation time.

Original languageEnglish
Pages (from-to)409-415
Number of pages7
JournalFood Microbiology
StatePublished - Sep 2019

Bibliographical note

Funding Information:
This work was supported by Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry (IPET) through High Value-added Food Technology Development Program, funded by Ministry of Agriculture, Food and Rural Affair (MAFRA) (317030-3)..

Publisher Copyright:
© 2019 Elsevier Ltd


  • Bacillus subtilis
  • Dipicolinic acid (DPA)
  • Germination
  • Intense pulsed light (IPL)


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