Modelling gene-dependent PEF resistance of E. coli K-12

Lytras, Fotios ; Psakis, Georgios ; Gatt, Ruben ; Raso, Javier (Universidad de Zaragoza) ; Valdramidis, Vasilis

Resumen: The current study investigated the antimicrobial mechanisms of Pulsed Electric Fields (PEF) by evaluating the resistance of 22 Escherichia coli K12 mutants. Initial screening at PEF treatment (23 kV/cm, 53.3 μs, 95.4 kJ/kg), pH 7.0, revealed increased sensitivity (p < 0.05) of ΔclpB, ΔrpoS, and ΔdnaK expressed in Log10 reductions. Further inactivation kinetic analysis of 8 selected strains at pH 7.0 and 4.0 revealed a non-linear, polyphasic behaviour. This was described by a global modelling approach combining a log-linear primary model with a second-order polynomial model incorporating treatment time, total specific energy, and survival data as variables. The calculated model parameters (C1, C2, and C3) significantly differed (p < 0.05) among strains at pH 7.0, but not at pH 4.0. Furthermore, the calculated inactivation rates, kmax, varied in relation to the total specific energy. At pH 7.0, kmax was higher at low (0–40 kJ/kg) and high (140–180 kJ/kg) total specific energies, while at pH 4.0, it raised at high total specific energies (120–160 kJ/kg). In conclusion, E. coli response to PEF was dependant on the stress regulator rpoS. This response also involved genes which encode molecular chaperones such as dnaK, clpB and recA, related proteins for DNA repair. In conclusion, resistance to PEF was found to be influenced by pH and total specific energy, indicating that E. coli mounts a multifaceted response to PEF treatments, informing advanced microbial inactivation strategies for food safety.

Idioma: Inglés

DOI: 10.1016/j.fm.2026.105042

Año: 2026

Publicado en: FOOD MICROBIOLOGY 137 (2026), 105042 [11 pp.]
ISSN: 0740-0020

Financiación: info:eu-repo/grantAgreement/EC/H2020/955431/EU/Training Network Sustainable Technologies/TRANSIT

Tipo y forma: Artículo (Versión definitiva)

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