Delvotest® plates instructions for use
| 1. Determine the number of plates and/or blocks of 16 wells needed and cut them off with a sharp knife or scissors. Be careful not to damage remaining blocks.
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| 2. Remove the aluminum foil completely.
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| 3. Pipette the negative control and the sample to be tested into the wells (100 μl). Identify the position of each sample by the letters and figures on the edge of multi plates.
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| 4. Seal the plates/or blocks with the adhesive strips or sheets supplied with the test kit.
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5. Incubate with the plate/ or blocks following one of the recommended procedures: | ||
5A. Water bath | 5B. Delvotest® Microplate Incubator | 5C. Delvotest® Accelerator Smart |
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Float the plate/or blocks in a stirred lidded water bath - preheated to 64 °C ± 2 °C. Set timer to end incubation to read at Control Time when the sensitivity is optimal (see Points of Attention) | Place the plate/or blocks in the Delvotest® Microplate Incubator - preheated to 64 °C ± 2 °C. Set timer to end incubation to read at Control Time when the sensitivity is optimal (see Points of Attention). | Place the plate/or blocks in Delvotest® Accelerator Smart - preheated to 64 °C ± 2 °C. The Control Time is automatically determined, and the results are read when sensitivity is optimal. The incubation stops automatically. |
DELVOTEST(r) T
The best test sensitivity is reached when measuring at control time. Start reading the color result of the negative control milk sample (first ampoule/well) after an incubation time of 2 hours 45 minutes. If the color has not changed to yellow, the tests should be immediately returned to the incubating device until a partially yellow reading of the negative control sample is achieved (it is recommended to repeat the readings at intervals of 5 minutes). When the color of the negative control test has turned to yellow, all other tests (samples) can be read. At control time the sensitivity of the Delvotest® T is for Penicillin G at 4 ng/g, for Sulfadiazine at 100 ng/g and for Oxytetracycline at 100 ng/g. If no control time reading is followed, a fixed reading time of 3 hours and 15 minutes can be used for cow milk, which will reduce the sensitivity. To optimize reliability, dsm-firmenich advises to verify the correct functionality of the test, operations and incubation with negative control and positive control milk samples available at dsm-firmenich.
DELVOTEST(r) SP-NT
The best test sensitivity is reached when measuring at control time. Start reading the color result of the negative control milk sample (first well) after an incubation time of 2 hours 15 minutes. If the color has not changed to yellow, the test ampoules should be returned to the incubating device until a yellow reading of the negative control sample is achieved (it is recommended to repeat the readings at intervals of 5 minutes). When the color of the negative control ampoule has turned to yellow, all other ampoules (samples) can be read. At control time the sensitivity of the Delvotest® SP NT is for Penicillin G at 2 ppb (ng/g) and for Sulfadiazine at 100 ppb (ng/g). When using a fixed time reading of 3 hours, the sensitivity will be reduced. To optimize reliability, DSM advises to verify the correct functionality of the test, operations and incubation with negative control and positive control milk samples available at dsm-firmenich.
6. Read the results following one of the recommended procedures: | ||
6A/B. Visual reading | C. Delvotest® Accelerator Smart | |
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Withdraw the freshly incubated plate/ blocks from the water or dry plate incubator and read visually the results from the bottom of the blocks. Use the provided color card reference (see Points of Attention) | 6C. Automatically with DAS The plate/or blocks are read automatically during the incubation and the results are determined at control time. A detailed report is saved at the end of the incubation. Refer to the related DAS manual. | |
6A/B. Alternatively Read with Delvo®scan | ||
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6A. Delvo®Scan – after water bath Alternatively, remove excess water from the plate with a (paper) towel. Place the freshly incubated plate/or blocks in the system Delvo®Scan. (ver. 5.08, scanner EPSON V600, cutoff 0). Scan to read and save a report of the results. Refer to the related Delvo®Scan manual. | 6B. Delvo®Scan after dry plate incubation Alternatively, remove the plate/or blocks from the Delvotest® Microplate Incubator and place in the system Delvo®Scan (ver. 5.08, scanner EPSON V600, cutoff 0). Scan to read and save a report of the results. Refer to the related Delvo®Scan manual.
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Points of Attention: (Refer to the DSM Technical Bulletin Best Practice Advice)
- Use the enclosed color card to read the test results for Delvotest(r).
- The control time (CT) is the incubation time for the test to become yellow with antibiotic free milk (color card between --- and -). At control time the sensitivity of the test is optimal. Refer to the color card for the correct yellow color indicating negative. When incubated longer than CT the sensitivity of the test is decreased. The incubation time for sheep and goat milk takes about 10-30 min more than for cow milk.
- To allow more time for reading after incubation, the tests can be dipped in a cold bath of water with ice. The cold stops further change of the color.
- The 1/3 upper part of the agar gel in the well can sometimes be not entirely yellow. Read the test result from the bottom.
For more information, please contact your local Sales Representative or e-mail us at: info.food@dsm.com.
SAQ:
How should I prepare milk samples for test in plate?