title: Biodiversity of psychrotrophic bacteria of the Bacillus cereus group collected on farm and in egg product industry.
abstract: The aim of the present study was (i) to type, by genotypic and phenotypic methods, a collection of psychrotrophic bacteria belonging to the Bacillus cereus group collected in a farm and in 6 egg breaking industries during a period covering a warm and a cold season, and (ii) to characterize the egg product spoilage (growth in liquid whole egg) and the sanitary risk potential (cytotoxic activity on Caco-2 cells and adhesion on stainless steel) of each isolate of the collection. The investigation of specific psychrotrophic and mesophilic signatures together with the study of ability to grow at 6 °C and/or at 43 °C on optimal agar medium allowed highlighting twelve profiles, the major one corresponding to the species Bacillus weihenstephanensis (46.2% of the collection). The diversity of the profiles depended on the season and on the origin of the isolates. In terms of food spoilage, all the isolates were able to grow at the same level in liquid whole egg and in optimal medium, even at low temperature. Under the same conditions, the cytotoxic activity depended on the isolate, the medium and the temperature. At 10 °C, no isolate was cytotoxic at 10 °C in liquid whole egg and only one, belonging to the Bacillus weihenstephansensis species, in the optimal medium. All the isolates were able to adhere on stainless steel at various levels, from 2.6±0.2 log cfu/cm(2) to 4.9±0.1 log cfu/cm(2). A large majority (80.8%) was strongly adhering and could lead to the formation of biofilms in industrial equipments.
authors.affiliation: Laboratoire de Microbiologie, Agrocampus Ouest, INRA, UMR1253, Science et Technologie du Lait et de l'Œuf, F-35000 Rennes, France. sophie.jan@agrocampus-ouest.fr
authors.forename: S
authors.initials: S
authors.lastname: Jan
authors.forename: N
authors.initials: N
authors.lastname: Brunet
authors.forename: C
authors.initials: C
authors.lastname: Techer
authors.forename: C
authors.initials: C
authors.lastname: Le Maréchal
authors.forename: A Z
authors.initials: AZ
authors.lastname: Koné
authors.forename: N
authors.initials: N
authors.lastname: Grosset
authors.forename: M F
authors.initials: MF
authors.lastname: Cochet
authors.forename: A
authors.initials: A
authors.lastname: Gillard
authors.forename: M
authors.initials: M
authors.lastname: Gautier
authors.forename: J
authors.initials: J
authors.lastname: Puterflam
authors.forename: F
authors.initials: F
authors.lastname: Baron
mesh_terms: D001409:Bacillus cereus / Q000145:classification / Q000302:isolation & purification / Q000502:physiology; D001422:Bacterial Adhesion / Q000502:physiology*; D044822:Biodiversity; D003257:Consumer Product Safety; D004531:Eggs / Q000382:microbiology*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006801:Humans; D010802:Phylogeny; D018570:Risk Assessment; D012621:Seasons; D013193:Stainless Steel
chemical_list: D013193:Stainless Steel