Immunomagnetic separation methods for the isolation of Campylobacter jejuni from ground poultry meats

Campylobacter jejuni is now recognized as a leading foodbome pathogen, for which poultry products constitute the main transmission route. Two alternative immunomagnetic beads (IMB) were tested for direct detection of C jejuni ATCC 35918 in artificially inoculated ground poultry meats and culture suspension. Polyclonal anti- Campylobacter antibodies were used to coat tosylactivated Dynabeads. The same antibodies conjugated with biotin were used to label streptavidin-coated beads. After these beads were incubated with inoculated poultry slurry or culture suspension, Campylobacter-bead complexes were separated from other components with a magnet. The capture efficiency was tested by plating bead-captured cells and unbound cells in the supernatant onto Karmali agar. The effects of different coating procedures, incubation time (60, 90, 120 min), numbers of immunomagnetic beads (10(6) to 10(7) /ml) and innoculum levels (10(3) to 10(7) CFU/g or ml) were determined. Without pre-enrichment, this approach could detect 10(4) CFU/g of ground poultry meats. These methods represent a new approach to extracting, concentrating and isolating Campylobacter spp. directly from foods. (C) 2001 Elsevier Science BN. All rights reserved.