title: Immunomagnetic capture of Bacillus anthracis spores from food.
abstract: Food is a vulnerable target for potential bioterrorist attacks; therefore, a critical mitigation strategy is needed for the rapid concentration and detection of biothreat agents from food matrices. Magnetic beads offer a unique advantage in that they have a large surface area for efficient  capture of bacteria. We have demonstrated the efficient capture and concentration of Bacillus anthracis (Sterne) spores using immunomagnetic beads for a potential food application. Magnetic beads from three different sources, with varying sizes and surface chemistries, were functionalized  with monoclonal antibodies and polyclonal antibodies from commercial sources and used to capture and concentrate anthrax spores from spiked food matrices, including milk, apple juice, bagged salad, processed meat, and bottled water. The results indicated that the Pathatrix beads were more  effective in the binding and capture of anthrax spores than the other two bead types investigated. Furthermore, it was observed that the use of polyclonal antibodies resulted in a more efficient recovery of anthrax spores than the use of monoclonal antibodies. Three different magnetic capture  methods, inversion, the Pathatrix Auto system, and the new i CropTheBug system, were investigated. The i CropTheBug system yielded a much higher recovery of spores than the Pathatrix Auto system. Spore recoveries ranged from 80 to 100% for the i CropTheBug system when  using pure spore preparations, whereas the Pathatrix Auto system had recoveries from 20 to 30%. Spore capture from food samples inoculated at a level of 1 CFU/ml resulted in 80 to 100% capture for milk, bottled water, and juice samples and 60 to 80% for processed meat and bagged salad when  using the i CropTheBug system. This efficient capture of anthrax spores at very low concentrations without enrichment has the potential to enhance the sensitivity of downstream detection technologies and will be a useful method in a foodborne bioterrorism response.
authors.affiliation: Canadian Food Inspection Agency, National Centres for Animal Disease, Lethbridge Laboratory, P.O. Box 640, Township Road 9-1, Lethbridge, Alberta, Canada T1J 3Z4.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Shields
authors.forename: Kristen R
authors.initials: KR
authors.lastname: Hahn
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Janzen
authors.forename: Noriko
authors.initials: N
authors.lastname: Goji
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Thomas
authors.forename: Cesar Bin I
authors.initials: CB
authors.lastname: Kingombe
authors.forename: Chantal
authors.initials: C
authors.lastname: Paquet
authors.forename: Arnold J
authors.initials: AJ
authors.lastname: Kell
authors.forename: Kingsley K
authors.initials: KK
authors.lastname: Amoako
mesh_terms: D001408:Bacillus anthracis / Q000302:isolation & purification*; D023482:Bioterrorism; D003257:Consumer Product Safety; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods*; D013171:Spores, Bacterial / Q000302:isolation & purification*