Colilert® is easy to use, rapid and accurate

Proven

• US EPA-approved, 24-hour test for drinking and source waters.
• International approvals include U.S. EPA, Standard Methods for Examination of Water and Wastewater, AOAC, IBWA, and EBWA.
• Millions of tests are run worldwide every year.

Easy

• Ease of use simplifies training.
• Unit-dosed packaging eliminates media preparation.
• No repeat testing due to clogged filters or heterotrophic interference.
• Quality Control (QC) procedure can be done in 15 minutes.
  

Rapid

• Under one minute hands-on time.
• Detects coliforms and E. coli simultaneously in 24 hours or less.
• No confirmations needed.
• No glassware cleaning or colony counting.

Accurate

• Identifies E. coli specifically, which eliminates unneeded public notification due to Klebsiella pneumoniae.
• Suppresses up to 2 million heterotrophs per 100 mL.
• Eliminates the subjective interpretation found in traditional methods.
• Detects a single viable coliform or E. coli per sample.

Economical

• 20 to 50% less expensive than traditional methods. (According to AWWARF Research Application #4).
• 95% lower equipment costs.
• Minimizes evening and weekend work.
• Up to 12-month shelf life at room temperature.

Flexible

• A Colilert® Snap Pack can be used for presence/absence (P/A) or quantification testing.
• Quanti-Tray® provides counts to 200/100 mL without dilutions.
• Quanti-Tray®/2000 provides counts to 2,419/100 mL without dilutions.
• Colilert is also available predispensed in 10 mL Most Probable Number (MPN) tubes.

Scientific Basis: How Colilert® Works

Colilert uses the patented Defined Substrate Technology® (DST®) to simultaneously detect total coliforms and E. coli. Two nutrient-indicators, ONPG and MUG, are the major sources of carbon in Colilert and can be metabolized by the coliform enzyme β-galactosidase and the E. coli enzyme β-glucuronidase, respectively.

As coliforms grow in Colilert, they use β-galactosidase to metabolize ONPG and change it from colorless to yellow.

E. coli use β-glucuronidase to metabolize MUG and create fluorescence. Since most non-coliforms do not have these enzymes, they are unable to grow and interfere.

The few non-coliforms that do have these enzymes are selectively suppressed by Colilert's specifically formulated matrix.

This approach is different from traditional media, which provide a nutrient-rich environment that supports the growth of both target organisms and non-targets. When non-targets grow and mimic target organisms, false positives occur. Growth of non-targets can also suppress target organisms and give false negatives in traditional media. To suppress non-targets, traditional media often include high levels of salts, detergents, or other selective agents—which may inadvertently suppress target organisms and give further false negatives.

All IDEXX DST reagents can be used in a presence/absence (P/A) vessel, Quanti-Tray®, or Quanti-Tray®/2000.