With Quanti-Tray, a 100 mL sample is divided into 51 wells. Then the Standard Methods’ Most Probable Number (MPN) approach is used to determine the number of bacteria in the original sample. Automation minimizes hands-on time and maximizes throughput (up to 4 samples per minute). The relatively large number of wells provides a high counting range of 1–200 (without dilutions) and very tight 95% confidence limits.
The Quanti-Tray/2000 is based on the same statistical model as the traditional 15-tube serial dilution. With the Quanti-Tray/2000, the sample is automatically divided into the proper portions when sealed by the Quanti-Tray Sealer PLUS. The Quanti-Tray system does not require the use of test tubes, Durham tubes, or any dilutions. By automatically distributing the sample into 97 wells of 2 different sizes, Quanti-Tray/2000 yields a counting range of 1–2,419 with a far better 95% confidence limit than a 15-tube serial dilution.
With Quanti-Tray/Legiolert, a 100 mL sample is divided into 96 wells. The Standard Methods’ Most Probable Number (MPN) approach is used to determine the number of bacteria in the original sample, using the MPN tables provided. Automation minimizes hands-on time and maximizes throughput (up to four samples per minute). The 96-well tray provides a counting range of 1–2,272 (without dilutions).
Quanti-Tray Sealer PLUSThe Quanti-Tray Sealer PLUS is the next generation sealer in the Quanti-Tray system. The sealer makes quantification with Quanti-Tray and Quanti-Tray/2000 possible while saving time and improving laboratory efficiency. Features include a 2–3 minute warm-up time, faster sealing of trays, energy efficiency, and an access panel that makes cleaning easy.
Add sample/reagent to tray.
Seal tray in Quanti-Tray Sealer PLUS.
Incubate, count positive wells, and refer to appropriate MPN table.
Are Quanti-Tray, Quanti-Tray/2000, and Quanti-Tray/Legiolert U.S. EPA approved?
The U.S. Environmental Protection Agency (EPA) has stated in writing that Quanti-Tray and Quanti-Tray/2000 can be used for compliance testing. Quanti-Tray approval letters from U.S. EPA are available on request. Quanti-Tray/Legiolert is not U.S. EPA approved as Legionella pneumophila water testing is not federally regulated in the United States. Please check for other regulations that may apply in your area.
How do Quanti-Tray, Quanti-Tray/2000, and Quanti-Tray/Legiolert compare to other standard methods?
Quanti-Tray provides a wider counting range than and comparable accuracy to membrane filtration (MF).
|Method||Lower Counting Range/100 mL.||Upper Counting Range/100 mL.|
Are Quanti-Tray, Quanti-Tray/2000, and Quanti-Tray/Legiolert trays sterile?
Quanti-Tray and Quanti-Tray/2000 are gas-sterilized using ethylene oxide. Quanti-Tray/Legiolert is treated using electron-beam technology to be Legionella pneumophila free.
What is the shelf life of Quanti-Tray, Quanti-Tray/2000, and Quanti-Tray/Legiolert?
The shelf life of Quanti-Tray and Quanti-Tray/2000 is up to 3 years from date of manufacture. The shelf life of Quanti-Tray/Legiolert is up to 1 year from date of manufacture. When storing opened bags of trays, fold over the opened end of the bag and seal with tape.
Does the temperature of the sealer affect the organisms that may be in the water sample?
No, the short time period that the tray is in the sealer will not harm the bacteria. The temperature in the wells will not increase more than 5°C during sealing.
Sometimes a few of the wells are not completely filled, what impact will that have on interpreting results?
One or two empty wells do not affect the test interpretation as long as the entire sample is in the tray. The effect on the Most Probable Number (MPN) is statistically insignificant. A partially filled well is interpreted the same way as a full well.
Can the trays be stacked in the incubator?
Yes, Quanti-Trays can be stacked up to 10 trays high. Use caution not to block the airflow in the incubator. Quanti-Tray/Legiolert trays must be stacked paper side down (with wells facing up) and should be oriented in alternating directions to increase stability.
How is Quanti-Tray interpreted?
Please refer to the package insert to determine result interpretation.
Some Colilert and Colilert-18 tests positive wells are darker than others. How does this affect interpretation?
Color intensity is a reflection of the different metabolic rates and final concentrations of the coliforms and E. coli in the different wells. Any yellow color or fluorescence in the sample well equal to or greater than the Quanti-Tray or Quanti-Tray/2000 Comparator is considered positive.
How do you interpret fluorescent wells that are not yellow when using the Colilert or Colilert-18 tests?
To determine the presence of E. coli, wells must be yellow and fluoresce. A fluorescent well that is not yellow is not an E. coli-positive well.
Can I use the Quanti-Tray 2X Sealer for Quanti-Tray/Legiolert?
No, Quanti-Tray/Legiolert can only be used with Quanti-Tray Sealer PLUS.
IDEXX Water has reference materials and approval documents to support the many products in our water portfolio. Find the document(s) you need by selecting the link below.
Snap pack and Quanti-Tray bundles are available.