title: Heat-resistance of psychrotolerant Bacillus cereus vegetative cells.
abstract: Spores of psychrotolerant strains of the foodborne pathogen Bacillus cereus can multiply during storage of cooked or pasteurized, refrigerated foods and can represent a risk if these cells are not eliminated during reheating of food product before consumption. We determined the heat-resistance of psychrotolerant B. cereus vegetative cells at different heating temperatures in laboratory medium and compared it with that of thermotolerant B. cereus vegetative cells. The z values, based on times for a 3 log10reduction, of the vegetative cells of the three psychrotolerant phylogenetic groups of B. cereus varied between 3.02 °C and 4.84 °C. The temperature at which a 3 log10reduction was achieved in 10 min varied between 47.6 °C and 49.2 °C for psychrotolerant vegetative cells and it was around 54.8 °C for thermotolerant vegetative cells. Moreover, 0.4 min at 60 °C would be sufficient for a 6 log10CFU/ml reduction of the most heat resistant psychrotolerant B. cereus vegetative cells. These data clearly showed that psychrotolerant B. cereus vegetative cells can be rapidly eliminated by a mild heat treatment such as food reheating.
authors.affiliation: UMR408 SQPOV « Sécurité et Qualité des Produits d'Origine Végétale », INRA, University of Avignon, 84000 Avignon, France.
authors.forename: Alizée
authors.initials: A
authors.lastname: Guérin
authors.affiliation: UMR408 SQPOV « Sécurité et Qualité des Produits d'Origine Végétale », INRA, University of Avignon, 84000 Avignon, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Dargaignaratz
authors.affiliation: UMR408 SQPOV « Sécurité et Qualité des Produits d'Origine Végétale », INRA, University of Avignon, 84000 Avignon, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Clavel
authors.affiliation: UMR408 SQPOV « Sécurité et Qualité des Produits d'Origine Végétale », INRA, University of Avignon, 84000 Avignon, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Broussolle
authors.affiliation: UMR408 SQPOV « Sécurité et Qualité des Produits d'Origine Végétale », INRA, University of Avignon, 84000 Avignon, France. Electronic address: Christophe.nguyen-the@avignon.inra.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Nguyen-The
mesh_terms: D001409:Bacillus cereus / Q000145:classification / Q000254:growth & development / Q000502:physiology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005506:Food Contamination / Q000517:prevention & control; D005516:Food Microbiology; D006358:Hot Temperature; D061352:Pasteurization; D010802:Phylogeny; D013171:Spores, Bacterial / Q000502:physiology; D000071436:Thermotolerance
keywords: Decimal reduction; Heat-inactivation; Phylogenetic groups; Weibull distribution; z value