🚧 Delvotest® Sample preparation

Here is a summary of the information you can find in this article:

Product formatPreparation Incubation Reading 
Delvotest® ampoules Instructions  Delvotest® GODelvotest® GO
 Delvotest® MiniS Visual at control time or  Delvo®scan 
Waterbath 
Delvotest® plates Instructions DAS DAS 
Waterbath  Visual at control time or  Delvo®scan 
Dry incubation 

Before you start testing 

Make sure you have found the control time of the batch you are about to use, your sample is representative and your tests are at room temperature.

  • Establishing control time 

We recommend taking along at least 1 (one) negative control for each incubation run, to verify the good performance of the test, to test procedure and to establish control time. Read here 'Establishing control time'

  • Collecting your milk sample

The milk sample should accurately represent the milk to be tested and must be homogenized before analysis. Follow these steps to ensure the sample is representative and properly homogenized. Especially when testing milk from individual animals: 

  • Use a clean container sufficient to hold a full milking. Do not use disinfectant/or cleaning reagents
  • Milk all four quarters of the udder. Do not use the foremilk strip from the teats as a sample. Do not use a milk sample from only one quarter of the udder. 
  • Mix the milk gently to avoid creating foam.
  • Use a clean sampling tool/sample mug when taking a new sample. 
  • Use good hygienic practices to avoid contaminating the milk samples.
  • Acclimatizing at room temperature prior to use

Before using Delvotest® ampoules and plates, remove the tests that you will use from the fridge to reach room temperature. Make sure that after preparation you return the remaining Delvotest® back in the fridge. Ampoules and plates should not stay out of the fridge for more than 3 hours.

Preparing your Delvotest® ampoules

1. Get your ampoules

To use one ampoule, remove it from the frame and open the aluminum foil as shown in pictures below. Open ampoules by punching a hole in the aluminum foil with the corner of the ampoule frame or a pair of scissors. Mark the ampoules with a number for sample identification. 

Are you testing with the Delvotest® GO? Follow the instructions on the app for the preparation. [Add here app links or relevant article]

2. Add the milk samples in your ampoules

Take a fresh disposable pipette for each milk sample. Hold from the upper bulb and do not touch the tip-end, which will be in contact with the milk to prevent contamination.

Add the milk (100 μl) into the pipette by squeezing the upper bulb once, hold it, dip the pipette tip ca.1 cm into the milk sample with the bulb facing up, as seen in the drawing below.  

Slowly release pressure on the bulb. The pipette (stem) will be filled with the appropriate volume (100 μl) of milk. After pipetting, a milk surplus will be drawn into the pipette reservoir (the small lower bulb). Repeat the pipetting when there is no milk in the reservoir or when there are air bubbles in the stem. 

  • Transfer the milk samples by gently and totally squeezing the same upper bulb, adding the milk straight onto the agar medium. Be careful not to touch the gel in the ampoule. 
  • Do not re-use pipettes. 

3. Incubate your ampoules 

Method Delvotest® GODelvotest® Mini SWaterbath 

Incubation temperaturePreheated at 64 °C +/- 2 °C
Stickers for ampoulesCover ampoules with stickers no stickers required Prevent water from the bath entering the ampoules 
Place the ampoules Follow the instructions in the appPut the ampoules into the incubator immediately after milk addition. 
Prepare for reading No further action required Add a timer to establish control time


4. Read you ampoule result

Reading method Delvotest® GOVisual reading Delvo®scan
When to readDelvotest® GO will send automatically the results in your app. Establish control time with negative control milk sampleEstablish control time with negative control milk sample. Read also here: Section- control time reading with Delvo®scan
Delvotest® T    The device will incubate ~15 min longer than the values stated in this section - Expected control time per species to make sure it is reading the test at control timeRead the ampoules at control time immediately after incubation using the colorcardPlace the freshly incubated ampoules in Delvo®Scan (v 5.08, scanner EPSON V600, cutoff 0). 
Refer to the related Delvo®Scan instructions here.
Delvotest® SPNT Read the ampoules at control time immediately after incubation using the digital reference card
How to readResults based on control time on your app. Visual reading is not possible.The 1/3 upper part of the agar gel in the ampoule can be somehow not yellow. Refer to the lower 2/3 parts to evaluate the test result.  Delvo®Scan is validated to scan and read the ampoules from the bottom 
Place in cold bath for later reading Not possible To allow more time for reading after incubation, the tests can be dipped it in a cold bath of water with ice. The cold stops further color change.


Preparing your Delvotest® plates

1. Get your plates

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.  Remove the aluminum foil completely for the plates or blocks of 16 wells that you are about to use.

Return unused plates/ block back to the fridge.


2. Add the milk samples on your plate

Gather your negative and positive milk control samples and the unknown samples to be tested. 

Pipette the samples into the wells (100 μl), using a clean pipette tip for each sample. Identify the position of each sample by the letters and figures on the edge of multi plates.

Seal the plates/or blocks with the adhesive strips or sheets supplied with the test kit.

Are you preparing samples for the DAS? Read important information on how many milk samples are required in Section 4 - control guidelines.

3. Incubate your plates 

MethodDelvotest® Accelerator Smart (DAS)WaterbathDelvotest® Microplate incubator
or other dry incubation 

Incubation temperaturePreheated to 64 °C ± 2 °C. 
Cover the plateUse the provided plate stickers in your Delvotest® box
Place the plateAdd the plate/or blocks in Delvotest® Accelerator Smart
and follow the instructions
Float the plate/or blocks in a stirred lidded water bathPut the plates/or blocks in the Delvotest® Microplate Incubator and close the lid
Prepare for reading No further action requiredAdd a timer to establish control time




4. Read your plate results

Method Delvotest® Accelerator Smart (DAS)Visual readingDelvo®scan
When to readThe results are read automatically at control time, when sensitivity is optimal. The incubation stops automatically Establish control time with the negative control milk samples on the plate.
Delvotest® T Refer to section - Expected control time per speciesRead the ampoules at control time immediately after incubation using the colorcardPlace the freshly incubated ampoules in Delvo®Scan (v 5.08, scanner EPSON V600, cutoff 0). 
Refer to the related Delvo®Scan instructions here.
Delvotest® SPNTRead the ampoules at control time immediately after incubation using the digital reference card


The 1/3 upper part of the agar gel in the well can be sometimes not entirely yellow. Read the test plates or blocks result from the bottom. 
Place in cold bath for later reading 
To allow more time for reading after incubation, the tests can be dipped it in a cold bath of water with ice. The cold stops further color change.