The Coliform Vials are a screening vial specific for coliform organisms. The vial has broad inclusivity and an assay time of 14-24 hours for most applications. The vial contains a peptone yeast extract base with lactose as a carbon source. The selective agents include bile salts, sodium lauryl sulfate and other gram-positive inhibitors. Acidification of the medium due to the lactose utilization changes the pH indicator from a purple to a yellow color. The color change is read by optical sensors in the instrument.
