Antigens can be captured and detected from complex samples, such as food and environmental samples, in about 30 minutes using apparatus and methods that include flow of the samples through a module containing antibodies coupled to beads. The samples flow through the modified beads at about 0.2 to 1.2 liters/minute, which fluidizes the bead bed. The antigens are captured by the antibodies, and then detection of the captured antibodies is carried out with chemiluminescence, fluorescence, or spectrophotometric techniques.