Disentangling the contributions of initial heterogeneities and dynamic stress adaptation to nonlinearities in bacterial survival curves.

Autor: Georgalis L; Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain., Yeak KYC; NIZO, Kernhemseweg 2, 6718 ZB Ede, the Netherlands; Food Microbiology, Wageningen University and Research, 6700 EV Wageningen, the Netherlands., Tsimpou C; Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain., Fernandez PS; Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain., Wells-Bennik M; NIZO, Kernhemseweg 2, 6718 ZB Ede, the Netherlands., Garre A; Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain. Electronic address: alberto.garre@upct.es.
Jazyk: angličtina
Zdroj: Food research international (Ottawa, Ont.) [Food Res Int] 2023 Nov; Vol. 173 (Pt 2), pp. 113385. Date of Electronic Publication: 2023 Aug 18.
DOI: 10.1016/j.foodres.2023.113385
Abstrakt: The deviations from log-linearity that are often observed in bacterial survivor curves can be explained using different arguments, both biological and experimental. In this study, we used Bacillus subtilis as a model organism to demonstrate that the generally accepted vitalistic arguments (initial heterogeneities in the stress resistance of the cells in the population) may fail to describe microbial inactivation in some situations. In this sense, we showed how dynamic stress acclimation during an isothermal treatment provides an alternative explanation for survivor curves with an upwards curvature. We also provided an innovative experimental approach based on preadaptation experiments to evaluate which hypothesis is more suitable for the bacterial response. Furthermore, we used our experimental results to define bounds for the possible stress acclimation that may take place during dynamic treatments, concluding that the magnitude of stress acclimation may be larger for dynamic treatments than for isothermal experiments. We also evaluated the contribution of the SigB general stress response system to heat resistance by comparing the heat survival of wt and the ΔsigB mutant. Both strains survived better in 51, 52.5 and 55 °C when cells were pre-adapted at 48 °C than non-pre-adapted cells. However, ΔsigB was less resistant to heat than wt due to the missing SigB general stress system. Although these conclusions were based on B. subtilis as a model organism, this study can be the first step towards the development of a novel methodology able to estimate dynamic effects using only isothermal experiments. This would improve the models developed within the predictive microbiology community, improving our ability to predict microbial inactivation during industrial treatments, which are most often dynamic.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)
Databáze: MEDLINE
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