Quanti-Disc/Quanti-Disc Reader Questions and Answers
Is Quanti-Disc approved?
Yes, Quanti-Disc is now an approved method in the UK for Colony Counts. Quanti-Disc was developed to correlate with Yeast Extract Agar-ISO Method 6222.
- UK Drinking Water Inspectorate; January 26, 2007
What is the volume of sample required for the Quanti-Disc test?
Results from the Quanti-Disc test are expressed as Most Probable Number (MPN) per 1 mL. Even though 4 mL of sample is added to the disc, the MPN table takes this into consideration and results are expressed per 1 mL.
Can I do dilutions with the Quanti-Disc test?
Yes. Dilute a sample in the same manner as you typically would. For example, as a 1:10 or 1:100 dilution. Pipette 4 mL of your final dilution into the Quanti-Disc. Make sure to multiply the results from the MPN table by the dilution factor. For example, a 1:10 dilution means all values in the MPN table should be multiplied by 10.
How do I inoculate the Quanti-Disc test?
Pipette 4 mL of sample onto the center of the disc. It is important to keep the pipette vertical and not at an angle. Make sure the sample comes in contact with all the channel openings, letting capillary action distribute the sample into all the wells. Replace the lid after 3 seconds (excess sample will be absorbed).
How do I incubate the Quanti-Disc test?
Incubate discs with the lid-side facing up. Incubate tests at 36±2°C for 44±4 hours and 22±2°C for 68±4 hours, as specified by the ISO Method 6222.
How do I read Quanti-Disc results?
- When reading results manually: Quanti-Disc results should be read with a 6-watt 365-nm UV lamp. Hold the lamp 5 inches (13 cm) above the disc in a dark environment and count the number of fluorescent wells. Face the lamp away from your eyes and toward the sample. Refer to the MPN table to convert positive wells to MPN per mL.
- When using the Quanti-Disc Reader: Start the Quanti-Disc Reader program and create a batch file to save your results to. Then, enter the Quanti-Disc sample information manually or using a bar-code reader. Insert the Quanti-Disc sample through the protective curtain onto the base template. Click the Count Positive Wells button or press the space bar on your keyboard. The reader reads the Quanti-Disc sample and displays and saves the number of positive wells and the MPN/mL.
Is Quanti-Disc sterile?
Yes, the base and lid are gamma-irradiated. There are 20 discs per foil sleeve. Any unused plates should remain in the bag and the bag should be closed. Do not leave any unused plates exposed to the environment.
What is the shelf life of Quanti-Disc?
The shelf life is up to twenty-four months from the date of manufacture.
What are the recommended storage conditions for Quanti-Disc media?
Store at 2°–8°C away from light.
Is Quanti-Disc made of recyclable plastic?
The bottom portion and the lid are made of polystyrene #6 and are recyclable.
What are the advantages of having the Quanti-Disc Reader?
The Quanti-Disc Reader reduces hands-on time and the possibility of human error by automating the reading and recording of data. The automated results are faster (read positive plates as quickly as negative plates) than manual reads. High, accurate throughput leads to better efficiencies in your laboratory.
What are the system requirements for the Quanti-Disc Reader software?
Minimum system requirements are:
- 500 MHz Intel® Pentium® III computer
- 512 MB memory
- 1.5 GB of available hard disk space recommended
- 1024 x 768, 24-bit true color graphics display
- CD-ROM drive
- One available USB 2.0 port
- Microsoft® Windows® 2000 service pack 3 or XP Professional service pack 2
- Microsoft® Excel (any version)
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