The system utilizes specified enrichment media to provide E. coli O157:H7 with readily available nutrients and other factors required for its survival and rapid growth. Used with Reveal media, the system can provide results in 12 to 20 hours.
A portion (200 µL) of the enriched culture is placed into the sample cup followed by a chemical treatment. The test device is placed into the sample cup during the chemical treatment and is incubated at 42°C for 15 minutes. The sample is wicked through the reagent zone that contains specific anti-E. coli O157:H7 antibodies conjugated to colloidal gold particles.
If antigens are present in the sample, they will bind to the gold-conjugated antibodies. This antigenantibody complex then leaves the reagent zone and travels across the membrane, which contains a zone of anti-E. coli O157:H7 antibodies. The immune complex with gold conjugate is captured and aggregates in this zone, thus displaying a visible line. The remainder of the sample continues to migrate to the end of the membrane where it is deposited into a waste reservoir.
The reagent zone also contains a gold conjugate of a second antigen, which is eluted by the sample regardless of the presence of E. coli O157:H7 antigen to form a line in the control zone, ensuring the test is working properly.
