Charm Blue Yellow II Test

Products / Test and Kits / Antibiotic Tests / Inhibition Tests / Charm Blue Yellow II Test

Charm Blue Yellow II detects 29 antimicrobial drugs in milk at or below EU MRLs. It has the lowest false-positive rate of evaluated inhibition tests that detect antimicrobials in milk. This microbial inhibition assay is used for high volume screening of raw commingled and ultra-pasteurized cow milk. The test can also be used to test for goat and sheep milk using a modified procedure with an extended incubation time.

Add sample, incubate for the specified time, and then compare the vial color to reference colors or use an electric scanner to read the results.

Blue Yellow II kits consist of single-service wells that contain premeasured bacterial spores, media, and a pH indicator. The starting color in the well is blue. Milk is added to the well and incubated. If antibiotics are absent, spores germinate and grow, which changes the color to yellow. If antibiotics are present in the milk, microbial growth is inhibited and the sample remains blue.


  • Detects many major classes of antibiotics: beta-lactams, sulfonamides, tetracyclines, macrolides, and aminoglycosides
  • Detects 29 antimicrobial drugs at or below EU MRLs
  • Ideal for large volume testing
  • Easy: Just add milk and incubate
  • Results in 3 hours
  • Results read visually or with a color scanner

Regulatory Info

  • Detects 29 antimicrobial drugs at or below EU MRL. Central Reference Laboratory (CRL) guidelines available upon request.
  • Validated by the Institute for Agricultural and Fisheries Research (ILVO-T&V, Belgium) (report available on request)
  • Approved by Polish Veterinary Research Institute (PIWET)
  • Approved by Chief Veterinary Inspectorate (Warsaw, Poland)


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