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Behaviour of an Escherichia coli strain deleted in the salt stress response gene kdpA during production and ripening of a semi-hard cheese


Peng, Silvio; Weik, D; Stephan, Roger; Hummerjohann, J (2015). Behaviour of an Escherichia coli strain deleted in the salt stress response gene kdpA during production and ripening of a semi-hard cheese. Journal of Food Safety and Food Quality, 66(2):46-50.

Abstract

In order to survive cheese production and cheese ripening Escherichia coli needs to adapt to the encountered stress such as the raised salt concentrations. Such adaptation typically involves the induction of stress response genes. Therefore, impaired or lacking activity in such genes may considerably affect survival of E. coliupon stress exposure such as encountered during cheese production. In previous in vitrostudies, an association between E. coli stress response gene expression and survival observed in raw milk cheese was found, indicating that reduced or absent induction of the salt stress response gene kdpA might have an impact on survival of an E. coli strain during raw milk cheese production. In this study, therefore, the survival of an E. coli strain deleted in the kdpA gene was investigated in comparison to its wildtype strain during production and ripening of semi-hard cheese. After an initial increase in E. coli counts a slow decrease of 1.80 and 1.38 log10 cfu/g until the end of the 16 week ripening period was observed for the kdpA-deletion and the wild-type strain, respectively, without significant differences between these strains. This indicates that lack of the kdpA gene did not considerably affect E. coli survival in cheese and therefore other stress response mechanisms are probably of higher importance for survival of E. coli in raw milk cheese

Abstract

In order to survive cheese production and cheese ripening Escherichia coli needs to adapt to the encountered stress such as the raised salt concentrations. Such adaptation typically involves the induction of stress response genes. Therefore, impaired or lacking activity in such genes may considerably affect survival of E. coliupon stress exposure such as encountered during cheese production. In previous in vitrostudies, an association between E. coli stress response gene expression and survival observed in raw milk cheese was found, indicating that reduced or absent induction of the salt stress response gene kdpA might have an impact on survival of an E. coli strain during raw milk cheese production. In this study, therefore, the survival of an E. coli strain deleted in the kdpA gene was investigated in comparison to its wildtype strain during production and ripening of semi-hard cheese. After an initial increase in E. coli counts a slow decrease of 1.80 and 1.38 log10 cfu/g until the end of the 16 week ripening period was observed for the kdpA-deletion and the wild-type strain, respectively, without significant differences between these strains. This indicates that lack of the kdpA gene did not considerably affect E. coli survival in cheese and therefore other stress response mechanisms are probably of higher importance for survival of E. coli in raw milk cheese

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Additional indexing

Other titles:Verhalten eines im Salzstressantwort-Gen kdpA deletierten Escherichia coli Stammes während der Produktion und Reifung eines Halbhartkäses
Item Type:Journal Article, refereed, original work
Communities & Collections:05 Vetsuisse Faculty > Institute of Food Safety and Hygiene
Dewey Decimal Classification:570 Life sciences; biology
610 Medicine & health
Uncontrolled Keywords:Stress response mechanism, raw milk cheese, KdpA-ATPase system
Language:English
Date:2015
Deposited On:18 Feb 2016 16:59
Last Modified:05 Apr 2016 20:05
Publisher:Schlütersche Verlagsgesellschaft
ISSN:0003-925X
Publisher DOI:https://doi.org/10.2376/0003-925X-66-46

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