Current Microbiology

, Volume 59, Issue 4, pp 420–424

Gamma Radiation Used as Hygienization Technique for Foods Does Not Induce Viable but Non-Culturable State (VBNC) in Salmonella enterica subsp. enterica serovar Typhimurium


DOI: 10.1007/s00284-009-9454-3

Cite this article as:
Saroj, S., Shashidhar, R. & Bandekar, J. Curr Microbiol (2009) 59: 420. doi:10.1007/s00284-009-9454-3


Gamma radiation has been widely used for hygienization of food products. Whether gamma radiation stress induces VBNC state in Salmonella is of great concern. Therefore, the study was carried out to determine whether gamma radiation exposure induces VBNC state in Salmonella enterica subsp. enterica serovar Typhimurium (S. typhimurium). The parameters tested were culturability on agar medium, transcriptional activity by RT-PCR, cytoplasmic membrane integrity, and direct viable count using LIVE/DEAD BacLight™ bacterial viability kit. The LIVE/DEAD BacLight™ counts for S. typhimurium cells treated with 0.5 and 1.0 kGy radiation dose were 0.8 and 0.1% of the control, respectively. Plate counts for S. typhimurium cells treated with 0.5 and 1.0 kGy radiation dose were 0.7 and 0.05% of the control, respectively. No viable cells of S. typhimurium were detected by both plate count and LIVE/DEAD BacLight™ after radiation treatment with 2 kGy. No transcriptional activity was detected in cells treated with 2 kGy radiation dose. If there were VBNC cells present, then significant differences in the counts between the LIVE/DEAD BacLight™ microscopic counts and plate agar counts must be observed. No significant difference (P > 0.05) in the counts were observed. Thus, it can be concluded that treatment with 2 kGy results in complete killing and does not induce VBNC state in S. typhimurium.

Supplementary material

284_2009_9454_MOESM1_ESM.doc (56 kb)
LIVE/DEAD BacLight™ staining of radiation-stressed S. typhimurium. Live cells are stained green, and dead cells are stained red (DOC 55 kb)

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Graduate School of Pharmaceutical SciencesChiba UniversityChibaJapan
  2. 2.Food Technology DivisionBhabha Atomic Research CentreMumbaiIndia

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