The stressosome and SigB influence the baseline thermal resistance but not dynamic adaptation of Listeria monocytogenes: insights from kinetic modelling

Guillén, Silvia (Universidad de Zaragoza) ; Fernández, Pablo S. ; O'Byrne, Conor ; Garre, Alberto

Resumen: This study takes a first step towards incorporating a more mechanistic basis into current microbial inactivation models. We focus on the role of SigB and the stressosome in the heat resistance of Listeria monocytogenes using a reference strain (EGD-e), as well as five mutant strains where SigB and/or the stressosome were mutated. Data was analysed using the Geeraerd model to quantify the link between SigB/stressosome and thermal resistance. The ΔsigB strain had lower thermal resistance ( = 0.21 log10 min) than EGD-e (0.27 log10 min). Mutations known to negatively affect the stressosome function also reduced the D-value (0.18 log10 min for RsbS S56A). Survivor curves had also a shoulder, which was also affected by SigB/stressosome. Exponential phase cells of the RsbR1-only strain had the shortest shoulder, while the wild type strain had the longest, which suggests that RsbR1 paralogues play a role in thermal stress response. Every strain was able to develop stress acclimation during dynamic heat treatments at low heating rates (2 °C/min) suggesting that factors other than SigB are important for thermal adaptation. Its impact was comparable to the jump from exponential to stationary phase cells, underlining the relevance of stress acclimation. This emphasizes the need for predictive models to go beyond a “baseline” resistance, accounting for the ability of cells to change their resistance as a response to environmental signals. This study marks a first step towards that goal, by defining possible ranges of variation for the D-value and shoulder length of L. monocytogenes.

Idioma: Inglés

DOI: 10.1016/j.foodres.2025.117165

Año: 2025

Publicado en: Food Research International 221, Part. 1 (2025), 117165 [10 pp.]
ISSN: 0963-9969

Financiación: info:eu-repo/grantAgreement/ES/MICINN-AEI/PRTR-C17.I1
Financiación: info:eu-repo/grantAgreement/ES/MICIU/PID2023-149211OB-C31

Tipo y forma: Article (Published version)

Área (Departamento): Área Tecnología de Alimentos (Dpto. Produc.Animal Cienc.Ali.)