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Relationship between glass transition temperature, and desiccation and heat tolerance in Salmonella enterica
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| Title: | Relationship between glass transition temperature, and desiccation and heat tolerance in Salmonella enterica |
| Authors: | Lee, Kyeongmin Browse this author | | Shoda, Masaki Browse this author | | Kawai, Kiyoshi Browse this author | | Koseki, Shigenobu Browse this author →KAKEN DB |
| Issue Date: | 29-May-2020 |
| Publisher: | PLOS |
| Journal Title: | PLoS ONE |
| Volume: | 15 |
| Issue: | 5 |
| Start Page: | e0233638 |
| Publisher DOI: | 10.1371/journal.pone.0233638 |
| Abstract: | Pathogenic bacteria such as Salmonella enterica exhibit high desiccation tolerance, enabling long-term survival in low water activity (a(w)) environments. Although there are many reports on the effects of low a(w) on bacterial survival, the mechanism by which bacteria acquire desiccation tolerance and resistance to heat inactivation in low-a(w) foods remains unclear. We focused on the glass transition phenomenon, as bacteria may acquire environmental tolerance by state change due to glass transition. In this study, we determined the glass transition temperature (T-g) in S. enterica serovars under different aw conditions using thermal rheological analysis (TRA). The softening behaviour associated with the state change of bacterial cells was confirmed by TRA, and T-g was determined from the softening behaviour. Tg increased as the aw decreased in all S. enterica serovars. For example, while the T-g of five S. enterica serovars was determined as 35.16 degrees C to 57.46 degrees C at 0.87 a(w), the T-g of all the five serovars increased by 77.10 degrees C to 83.30 degrees C at 0.43 a(w). Furthermore, to verify the thermal tolerance of bacterial cells, a thermal inactivation assay was conducted at 60 degrees C for 10 min under each a(w) condition. A higher survival ratio was observed as a(w) decreased; this represented an increase in T-g for Salmonella strains. These results suggest that the glass transition phenomenon of bacterial cells would associate with environmental tolerance. |
| Rights: | https://creativecommons.org/licenses/by/4.0/ |
| Type: | article |
| URI: | http://hdl.handle.net/2115/78888 |
| Appears in Collections: | 農学院・農学研究院 (Graduate School of Agriculture / Faculty of Agriculture) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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