Growth delay analysis of high-salt injured Escherichia coli O157:H7 in fermented soybean paste by real-time PCR and comparison of this method with other estimation methods
| Autor: | Yasuhiro Inatsu, Fia Noviyanti, Susumu Kawasaki, Yukie Hosotani, Shigenobu Koseki |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
biology
Chemistry Atp content 04 agricultural and veterinary sciences Bacterial growth biology.organism_classification medicine.disease_cause 040401 food science 0404 agricultural biotechnology Real-time polymerase chain reaction medicine Fermentation Food science Growth delay Estimation methods Escherichia coli Bacteria Food Science |
| Zdroj: | SC30201812260002 NARO成果DBd |
| ISSN: | 0023-6438 |
| Popis: | The aim of this study was to develop an estimation method for bacterial injury levels of Escherichia coli O157:H7 in food products. Bacterial growth was monitored in recovery medium and quantified by real-time PCR to quantify the growth delay phenomenon as growth delay time (GDT). The relationship between GDT and stress levels (salt-concentration: 9, 13, 15, and 17%; stress exposure times:0, 6, 12, 18, and 24 h) was determined. The GDT increased with stress exposure time, and the higher the salt concentration was, the faster the GDT increased. Moreover, bacterial injury levels in 15% NaCl-containing media were estimated by a conventional culture-based method, bacterial membrane destruction assay, NADPH content assay, and intercellular ATP content assay. In these estimations, the result suggested a decrease in bacterial activity and increase in bacterial membrane destruction from 6 to 12 h of exposure, which was consistent with the results of the GDT monitoring method. Furthermore, the estimation of bacterial injury levels in high-salt food (fermented soybean paste) was investigated, and GDT extension was successfully observed until the bacteria completely reached sublethal conditions. Therefore, GDT monitoring by real-time PCR showed the ability to estimate bacterial injury levels along with other existing methods. |
| Databáze: | OpenAIRE |
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