title: Genotypic and phenotypic characterization of foodborne Geobacillus stearothermophilus.
abstract: Geobacillus stearothermophilus is the main thermophilic spore former involved in flat sour spoilage of canned foods. Three typing methods were tested and applied to differentiate strains at intra-species level: panC sequence analysis, REP-PCR and M13-PCR. panC gene was highly conserved within the studied strains, suggesting a low intra-specific diversity. This was supported by REP-PCR primary assays and M13-PCR results. M13-PCR profile analysis succeeded in differentiating six closely related groups (at 79% threshold similarity) among 127 strains from a range of spoiled canned food products and from different canneries. Phenotypic traits were investigated among 20 selected strains representing groups and origins. Ranges of growth under different temperatures (from 40 °C to 70 °C), pH (from 5.0 to 6.5), NaCl concentrations (from 1 to 5%) and sporulation conditions poorly differed between strains, but wet heat resistance of spores showed a 20-fold variation between strains. Furthermore, in this study, strains that belonged to the same M13-PCR genetic group did not share phenotypic characteristics or common origin. The work emphasizes a low diversity within the G. stearothermophilus species but data from this study may contribute to a better control of G. stearothermophilus spoilage in canned food.
authors.affiliation: CTCPA, Site Agroparc, ZA de l'aéroport - BP21203, 84911 Avignon Cedex 9, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Durand
authors.affiliation: CTCPA, Site Agroparc, ZA de l'aéroport - BP21203, 84911 Avignon Cedex 9, France.
authors.forename: Stella
authors.initials: S
authors.lastname: Planchon
authors.affiliation: INRA, UMR 408, Sécurité et Qualité des Produits d'Origine Végétale, F-84000 Avignon, France; Université d'Avignon et des Pays de Vaucluse, UMR 408, Sécurité et Qualité des Produits d'Origine Végétale, F-84000 Avignon, France.
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Guinebretiere
authors.affiliation: INRA, UMR 408, Sécurité et Qualité des Produits d'Origine Végétale, F-84000 Avignon, France; Université d'Avignon et des Pays de Vaucluse, UMR 408, Sécurité et Qualité des Produits d'Origine Végétale, F-84000 Avignon, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Carlin
authors.affiliation: CTCPA, Site Agroparc, ZA de l'aéroport - BP21203, 84911 Avignon Cedex 9, France. Electronic address: fabienne.remize@univ-reunion.fr.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Remize
mesh_terms: D001483:Base Sequence; D016000:Cluster Analysis; D005516:Food Microbiology; D057141:Food, Preserved / Q000382:microbiology*; D014644:Genetic Variation; D005838:Genotype; D001411:Geobacillus stearothermophilus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010641:Phenotype; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000494:pharmacology; D013171:Spores, Bacterial
chemical_list: D012965:Sodium Chloride
keywords: Canned food spoilage; Diversity; Geobacillus stearothermophilus; M13 genetic typing; Spore-forming bacteria