IDEXX Colilert simultaneously detects or quantifies both total coliforms and Escherichia coli (E.coli) in just 24 hours. Preparation of the test takes less than one minute and removes the need for time-consuming confirmations and colony counting.

The IDEXX Colilert Test is used around the world for the detection of coliforms and E.coli. Colilert uses the patented Defined Substrate Technology (DST) to simultaneously detect total coliforms and E.coli. 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 that may inadvertently suppress target organisms and give further false negatives.

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

• Less than 1 minute of 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, eliminating unnecessary public notification due to non-target organisms.
• Suppresses up to 2 million heterotrophs per 100 ml and 5 million per 250 ml.
• Eliminates the subjective interpretation found in traditional methods.
• Detects a single viable coliform or E.coli per sample.

Economical

• Minimises evening and weekend work.
• Up to 12-month shelf life at room temperature
• Available sample size: 100 or 250ml
• Available pack size: 20 (only for 100ml), 100 or 200

Colilert can be used as a presence/absence test or results can be quantified using the Idexx Quanti-Tray and an MPN table. A negative sample appears clear while a positive sample for coliforms is yellow. A positive E.coli sample will be yellow and will fluoresce under ultraviolet light.

How it works

The Colilert test uses proprietary 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 metabolised by the coliform enzyme ß-galactosidase and the E.coli enzyme ß-glucuronidase, respectively.

As coliforms grow in the Colilert Test, they use ß-galactosidase to metabolise ONPG and change it from colourless to yellow.

E.coli use ß-glucuronidase to metabolise 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 the Colilert Test'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 nontargets. When nontargets grow and mimic target organisms, false positives occur. Growth of nontargets can also suppress target organisms and give false negatives in traditional media. To suppress nontargets, traditional media often include high levels of salts, detergents, or other selective agents that may inadvertently suppress target organisms and give further false negatives.

Only IDEXX reagents have been validated and approved for use with Quanti-Tray and Quanti-Tray/2000.