AiM - Analytik in Milch

<body topmargin="0" leftmargin="0"> <p><a target="_top" href="../../index.html"><font color="#000000">Home</font></a><font color="#000000"><br> <br> <a target="_top" href="../../products/index.htm"><font color="#000000">Products</font></a><br> <a target="_top" href="../../information"><font color="#000000">Information</font></a><br>   <a target="_top" href="../index.htm">Basics</a><br>   <a target="_top" href="../legalbasis">Legal Basis (Europe)</a><br>   <a target="_top" href="../mrls">MRLs</a><br>   <a target="_top" href="../detection">Detection Sensitivity</a><br>   <a target="_top" href="index.htm">Test Performance</a><br> <br> <a target="_top" href="../../company"><font color="#000000">Company</font></a><br> <a target="_top" href="../../contact"><font color="#000000">Contact</font></a><br> <a target="_top" href="../../imprint"><font color="#000000">Imprint</font></a><br> <a target="_top" href="../../distributors"><font color="#000000"> Distributors</font></a></font></p> <p><br> Test Performance <br> <br> Penicillin G Standard, full cream milk lyophilisate 4 ng/ml - Article No. 9143<br> <br> <br> The Penicillin G Standard is delivered as a lyophilisate and must be re-suspended before use:<br> 1) Flip and tear off green aluminium seal of the vial:<br> <br> <br> <br> 2) Remove the buckler from the vial and lay it up side down on the bench:<br> <br> <br> 3) Pipette 4.5 ml sterile water into the vial and close the vial with the buckler:<br> <br> <br> 4) Shake the vial until all lyophilisate is re-suspended:<br> <br> Final concentration after re-suspending is:<br> 0.0067 I.U. Penicillin G/ml resp. 4 +/- 0.3 ng Penicillin G/ml (4 ppb)<br> 5) Pipette 100 µl of the Penicillin G Standard 4 ng/ml as positive control into one of the test wells:<br> <br> The well containing the Penicillin G Standard must remain blue after incubation.<br> <br> <br> <br> Penicillin G Standard Concentrate, full cream milk lyophilisate 4 µg/ml - Article No. 9144 <br> <br> <br> The Penicillin G Standard Concentrate is delivered as a lyophilisate and must be re-suspended and then diluted 1/1000 before use:<br> <br> 1) Flip and tear off green aluminium seal of the vial:<br> <br> <br> <br> 2) Remove the buckler from the vial and lay it up side down on the bench:<br> <br> <br> 3) Pipette 4.5 ml sterile water into the vial and close the vial with the buckler:<br> <br> <br> 4) Shake the vial until all lyophilisate is re-suspended:<br> <br> Concentration after re-suspending is:<br> 6.7 I.U. Penicillin G/ml resp. 4 +/- 0.3 µg Penicillin G/ml<br> 5) Dilute re-suspended Penicillin G Standard Concentrate 1/1000: <br> E.g. pipette 0.2 ml of the re-suspended Penicillin G Standard Concentrate into 200 ml of the corresponding inhibitor free substrate (e.g. raw milk, etc) and mix well.<br> <br> <br> Final concentration after dilution is:<br> 0.0067 I.U. Penicillin G/ml resp. 4 +/- 0,3 ng Penicillin G/ml (4 ppb)<br> <br> 6) Pipette 100 µl of the Penicillin G Standard 4 ng/ml as positive control into one of the test wells:<br> <br> <br> The well containing the Penicillin G Standard must remain blue after incubation.<br> <br> <br> BRT test tubes<br> <br> <br> <br> take the number of tubes you need from the packing<br> remove closure from tube<br> pipette 0.1 ml of each sample in different tubes, double check is useful<br> use for every sample another pipette tip to avoid contaminations<br> <br> <br> put 0.1 ml of the negative control (Inhibitor Free Milk) in a tube<br> put 0.1 ml of the positive control (Penicillin G Standard) in another <br> tube<br> close tubes with closure tightly<br> <br> <br> incubate the tubes in a water bath or thermo-block at 65 °C until the tube with the negative control has turned completely yellow (ca. 2:30 h +/- 15 min).<br> <br> <br> <br> Interpretation of the results: see below<br> <br> BRT MRL-Screening Test, BRT Inhibitor Test<br> <br> <br> <br> cut off the number of strips you need<br> remove sealing foil from strips / plate. Floating the plate for 30 seconds in the water bath will make removal of the sealing foil easy<br> pipette 0.1 ml of each sample in different cavities, double check is <br> useful<br> use for every sample another pipette tip to avoid contaminations<br> <br> <br> put 0.1 ml of the negative control (Inhibitor Free Milk) in a cavity<br> put 0.1 ml of the positive control (Penicillin G Standard) in another <br> cavity<br> put the perforated seal over the plate<br> <br> <br> incubate the plates / strips in a water bath or thermo-block at 65 °C <br> until the cavity with the negative control has turned completely into <br> yellow (BRT inhibitor test ca. 2:30 h +/- 15 min and BRT screening test 2:30 h +/- 15 min).<br> <br> <br> <br> <br> to make the interpretation of the results easier it is possible to wash the plate / strips with water carefully. Do this, holding the plate vertically under warm running water for 2 seconds and then flick the water off.<br> <br> <br> <br> <br> <br> interpretation of the results occurs at the bottom of the plates / strips so turn the plate over and read from the bottom.<br> <br> <br> BRT Inhibitor Test with Prediffusion<br> <br> <br> cut off the number of strips you need<br> remove sealing foil from strips / plate. Floating the plate for 30 seconds in the water bath will make removal of the sealing foil easy<br> pipette 0.1 ml of each sample in different cavities, double check is useful<br> <br> <br> use for every sample another pipette tip to avoid contaminations<br> put 0.1 ml of the negative control (Inhibitor Free Milk) in a cavity<br> put 0.1 ml of the positive control (Penicillin G Standard) in another cavity<br> <br> <br> let the samples diffuse one hour in the fridge<br> <br> <br> wash the plate / strips with water efficiently. Do this, holding the plate <br> vertically under running water and then flick the water off (2 - 3 times).<br> <br> put the seal over the plate and close tightly<br> <br> <br> <br> <br> incubate the plate / strips in a water bath or thermo-blockat 65 °C until the cavity with the negative control has turned completely into yellow (ca. 2:30 h +/- 15 min).<br> <br> <br> <br> <br> <br> Interpretation<br> To interpret the results of the incubated strips or plates in a correct way, it is necessary to have a positive and negative control on every plate and these controls have reacted correct. Interpretation of the results occurs on the bottom of the plate / strips.<br> <br> 1) positive control (fourfold) always dark clear blue<br> 2) negative control (fourfold) always orange yellow<br> 3) positive samples<br> 4) suspicious samples<br> <br> 1) negative control / negative sample<br> 2) suspicious sample<br> 3) positive control / positive sample<br> <br> Extra Tipps<br> 64-65 °C are ideal for this test - if incubating at lower temperature you will need to incubate the plates for longer.<br> Water bath temperature is critical - please ensure it is at 65 °C at the surface.<br> A high bacteria count (> 4 x 107cfu/ml) in sample milk will give a positive BRT result.<br> High somatic cells will give a positive result.<br> A sample pH of < 5.8 will give a grey colour and not good reduction.<br> Betalactams at low levels will give a brownish colour ( < 1 ppb)<br> Betalactam derivatives will give a clear dark blue colour<br> Sulphonamides can give a brownish colour<br> Storage of the plates should ideally be at 6-8 °C - if the plates are stored at 4 °C or lower temperatures changes can occur in the structure of the agar making reading difficult.<br> Water bath should not have inhibitors or bacteriocides in the water as this can cause false positive results.<br> Use a calibrated 100µl pipettor for samples with a new disposable tip for each sample.<br> Fat on the top of the milk can change colour and go blue so always read the plates from the bottom and remember that a true positive is all of the agar in the well being blue.<br> Pipette standards into the plate wells with the plate firmly on the bench to avoid spillover into other wells and subsequent false result.<br> Plates can be read using a spectrophotometer at 450nm measuring wavelength and 620 nm reference wavelength.<br>  </p> </body>