Development and characterization of a bioselective adsorption matrix for removal of Bacillus cereus spores from buffer and milk

Bioselective adsorption was evaluated as a possible technology for food processing to enhance safety using Bacillus cereus in milk as a model system. Cataphore(TM) Microbeads class -400 were derivatized by attaching 3-aminopropyl groups (2.7 nm(2)/molecule) onto the surface of the bead. Carbohydrates on the Fc region of monoclonal antibody 183 against B. cereus T spores were oxidized with potassium meta-periodate to allow for an oriented antibody immobilization (270 nm(2)/molecule). The adsorption matrix was characterized for its ability to bind B. cereus spores in comparison to a control matrix containing immobilized bovine serum albumin. When 2.5 x 200 spores in skim milk were added to 1 mL of each matrix, the IgG-matrix was capable of removing 96% of that amount, 70% of which were bound with high affinity and were only eluted with 0.1 mol/L acetic acid. In contrast, the control matrix removed 90% of the spores added bur only 7% were retained after washing the matrix. In addition, the IgG-matrix showed an excellent regeneration ability; the binding level did not decrease significantly after 28 trials with buffer or milk. Calculations determined that the bioadsorbant was capable of removing 8 x 10(6) spores/m(2). Thus, bioselective adsorption has promise as a technology to enhance safety of liquid foods or to improve analytical methodology. (C) 1997 Academic Press Limited.