Technical description colony counter Irina
The automated colony counter Irina has two carrousels; one carrousel is used for the Petri-dishes to be counted and the other to re-stack the scanned Petri-dishes. This is essential for high through-put rates, since substitution is not possible in this case. Each carrousel has a capacity of 540 Petri-dishes. The Petri-dishes are de-stacked one by one and each Petri-dish is placed on a turntable where the barcode is read. This barcode can be located on the top-lid or on the side of the Petri-dish. As the barcode is now known and we also know what the agar is, we can also send the parameters for the camera to the camera.
In this position the top-lid is also removed by means of a vacuum. The following position is used to physically slide the Petri-dish into the camera. The automated colony counter can work with two types of camera’s (colony counters), the Protocol 3 from Synbiosis and the Scan 1200 from Interscience. In our opinion the best colony counters available on the market.
The top-lid is taken in a parallel movement together with the lower part of the Petri-dish and, after scanning, the top-lid is re-united wit hits original lower part. This is certainly of great importance if the barcode is located on the top-lid. If so desired, the Petri-dish can be selected from the stack on the basis of this coding. A photo is taken in the scanner, the count is done and a file is created in which the barcode, the count and the photos are saved. All the data from the Petri-dishes together form a large file which can be imported via an SQL server into LIMS, from where the report can be made. After the lower part of the Petri-dish has been removed from the camera, the top-lid is replaced.
We then have two automated options and one free option:
- The sample has been correctly processed and approved and the Petri-dish is stacked in carrousel two, the carrousel for scanned Petri-dishes.
- The barcode can, for whatever reason, not be read and the Petri-dish is placed on a separate stack. Later on, the barcode can be entered manually on the touchscreen, by making use of the numbers under the barcode. The scan can then still be carried out and the data included in the procedure. We have built in this option to make sure that the analyst does not need to search in the stack of 500+ for the missing Petri-dish. The added advantage is that the analyst can then see the “scan-error”-situation.
- The sample has been correctly processed and has a zero count on the colony counter. When the analyst has established a zero count on the colony counter and does not to have to check the Petri-dishes manually, they can be discarded in the garbage bin right away.
The first carrousel can be filled when the analyst sees that there are empty spaces. Before filling the first carrousel, the second carrousel should, of course, be emptied as much as possible. Otherwise the system will shut down. Due to the fact that several operations are going on simultaneously, we reach a high production speed, between 5 and 10 seconds per scan. If we work on the basis of a safe calculation, we scan and count 500 Petri-dishes in 90 minutes. Great attention has also been paid to ease of cleaning with this machine.
The automated colony counter is connected to your LIMS via the previously mentioned SQL-server to gather the necessary details for the scanner. The photos and results are also sent back to your LIMS. One of the greatest advantages of this machine is its documentation possibility. A photo is taken, then linked to LIMS, the name of the person who made the validation of the sample as well as the time of the validation. Should there ever be a discussion about this sample, then the whole process is logged and can be fully displayed. When the camera is capable of counting a large part of the samples correctly, the machine is then of great value to you. A laboratory will almost certainly wish to validate all the Petri-dishes which can be done by means of a photo on which every counted colony is shown. You can add or subtract with just one click of the mouse. A “zero”-count Petri-dish can be validated in just two seconds, while sitting at your desk. We have optimalised this system to such a degree that the photos can be validated on several computers at once, while the colony counter is loading your database with new data.