title: Modeling heat resistance of Bacillus weihenstephanensis and Bacillus licheniformis spores as function of sporulation temperature and pH.
abstract: Although sporulation environmental factors are known to impact on Bacillus spore heat resistance, they are not integrated into predictive models used to calculate the efficiency of heating processes. This work reports the influence of temperature and pH encountered during sporulation on heat resistance of Bacillus weihenstephanensis KBAB4 and Bacillus licheniformis AD978 spores. A decrease in heat resistance (δ) was observed for spores produced either at low temperature, at high temperature or at acidic pH. Sporulation temperature and pH maximizing the spore heat resistance were identified. Heat sensitivity (z) was not modified whatever the sporulation environmental factors were. A resistance secondary model inspired by the Rosso model was proposed. Sporulation temperatures and pHs minimizing or maximizing the spore heat resistance (T(min(R)), T(opt(R)), T(max(R)), pH(min(R)) and pH(opt(R))) were estimated. The goodness of the model fit was assessed for both studied strains and literature data. The estimation of the sporulation temperature and pH maximizing the spore heat resistance is of great interest to produce spores assessing the spore inactivation in the heating processes applied by the food industry.
authors.affiliation: UMT 08.3 PHYSI'Opt, Z.A. de Creac'h Gwen, F-29196 Quimper Cedex, France. Eugenie.baril@univ-brest.fr
authors.forename: Eugénie
authors.initials: E
authors.lastname: Baril
authors.forename: Louis
authors.initials: L
authors.lastname: Coroller
authors.forename: Olivier
authors.initials: O
authors.lastname: Couvert
authors.forename: Ivan
authors.initials: I
authors.lastname: Leguérinel
authors.forename: Florence
authors.initials: F
authors.lastname: Postollec
authors.forename: Christophe
authors.initials: C
authors.lastname: Boulais
authors.forename: Frédéric
authors.initials: F
authors.lastname: Carlin
authors.forename: Pierre
authors.initials: P
authors.lastname: Mafart
mesh_terms: D001407:Bacillus / Q000254:growth & development* / Q000502:physiology; D003080:Cold Temperature; D015169:Colony Count, Microbial; D005516:Food Microbiology / Q000379:methods*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D013171:Spores, Bacterial / Q000254:growth & development*