The E. coli Vial detection system is a peptone yeast extract base with lactose as the carbon source. The selective agents include bile salts, sodium lauryl sulfate, and other Gram-positive inhibitors. Acidification of the medium due to lactose utilization changes the pH. Bromocresol purple (BCP) is used as the pH indicator. A more concentrated inhibitory system and 44.5°C temperature add to the medium's selectivity. The BCP changes from purple to yellow as acid is produced from E. coli metabolism (vials look similar to coliform vials).

In an AOAC Research Institute Performance Tested MethodSM study, Soleris® for E. coli was found to be an effective method for detection of E. coli in the following sample types: cocoa powder, echinacea, mozzarella cheese, pasteurized liquid egg, condensed milk and frozen green beans. Up to 1 mL of a 1:10 sample homogenate may be added to the Soleris vial for all commodities except echinacea, where a further 1:10 dilution is required to avoid matrix inhibition of E. coli growth.