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

Author:
Saroj, Sunil, Shashidhar, R., Bandekar, Jayant
Source:
Current microbiology 2009 v.59 no.4 pp. 420-424
ISSN:
0343-8651
Subject:
Salmonella enterica subsp. enterica serovar Typhimurium, agar, cell membranes, foods, gamma radiation, plate count, transcription (genetics), viability
Abstract:
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[trade mark sign] bacterial viability kit. The LIVE/DEAD BacLight[trade mark sign] 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[trade mark sign] 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[trade mark sign] 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.
Agid:
637225