IDEXX have introduced its total coliform/E. coli test - Colilert-18/Quanti-Tray (ISO 9308-2:2012), for the 18 hour detection of E. coli and total coliforms in water, to the food processing and packaging industries.

The test, which has been specified as a reference method, under EN ISO 9308-2, in the European Drinking Water Directive 2015/1787, became the ISO 9308-2 standard for the detection of E. coli and total coliforms in water in 2012, and later as EN ISO 9308-2 in 2014, following extensive validation, and provides quantified results in as little as 18 hours with no further confirmation of results required.

It is also U.S. EPA-approved and approved and included in Standard Methods for Examination of Water and Wastewater.

With its high sensitivity, specificity and rapid results, giving accurate and fast indications of any potential faecal contamination, Colilert-18 is simple to use and minimal amounts of training and equipment are required to allow operatives to set up and interpret the results in just 18 hours.

The product consists of a reagent powder, which is added to a standard 100ml water sample and then incubated for 18 hours in the case of presence/absence determination. This step takes less than 1 minute of hands-on time. The presence of E. coli and total coliforms is subsequently determined following incubation, with coliforms indicated by the sample turning yellow, and fluorescence indicating the presence of E. coli.

Where quantification of a sample is required, IDEXX has developed a simple device known as a Quanti-Tray®, which consists of 51 individually sealable cells. The Quanti-Tray can also be incubated for 18 hours after which the fluorescent cells can be counted and quantified.