University of Surrey

Test tubes in the lab Research in the ATI Dance Research

Heat inactivation of Escherichia coli K12 MG1655: Effect of microbial metabolites and acids in spent medium

Velliou, EG, Van Derlinden, E, Cappuyns, AM, Geeraerd, AH, Devlieghere, F and Van Impe, JF (2012) Heat inactivation of Escherichia coli K12 MG1655: Effect of microbial metabolites and acids in spent medium Journal of Thermal Biology, 37 (1). pp. 72-78.

Full text not available from this repository.

Abstract

Aim: The effect of spent medium, obtained after different time-temperature pre-histories, on the heat inactivation of Escherichia coli K12 MG1655 is studied. Methods and results: Stationary E. coli cells were heated in BHI broth (initial pH 7.5) at different time-temperature scenarios, i.e., (1) 30 °C to 55 °C at 0.14 °C/min, (2) 30 °C to 42 °C at 0.14 °C/min and (3) 30 °C to 42 °C at 0.8 °C/min. After the heat treatment, spent medium was filter-sterilized, non-stressed cells were added and inactivation experiments took place at 54 °C and 58 °C. In all scenarios, increased resistance was observed. The main characteristics of the spent medium - compared to the unmodified BHI broth - are (1) the presence of proteins (proven via SDS-PAGE) and (2) a lower pH of approximately 6. Possibly, the increased resistance is due to these proteins and/or the lower pH. Further experiments revealed that each factor separately may lead to an increased heat resistance. Conclusions: It can be concluded that this increased heat resistance resulted from both the presence of the heat shock proteins in the spent medium and the lowered pH. Experiments, which separate both effects, showed that mainly the lower pH resulted in the increased thermotolerance. Significance and impact of study: This study may lead to a better understanding and control of the heat stress adaptation phenomenon as displayed by E. coli at lethal temperatures. Therefore, it contributes to an improved assessment of the effect of temperature during thermal processes in the food industry. © 2011.

Item Type: Article
Authors :
NameEmailORCID
Velliou, EGe.velliou@surrey.ac.ukUNSPECIFIED
Van Derlinden, EUNSPECIFIEDUNSPECIFIED
Cappuyns, AMUNSPECIFIEDUNSPECIFIED
Geeraerd, AHUNSPECIFIEDUNSPECIFIED
Devlieghere, FUNSPECIFIEDUNSPECIFIED
Van Impe, JFUNSPECIFIEDUNSPECIFIED
Date : 1 January 2012
Identification Number : https://doi.org/10.1016/j.jtherbio.2011.11.001
Depositing User : Symplectic Elements
Date Deposited : 17 May 2017 13:23
Last Modified : 17 May 2017 15:10
URI: http://epubs.surrey.ac.uk/id/eprint/838998

Actions (login required)

View Item View Item

Downloads

Downloads per month over past year


Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800