Staphylococcus aureus · Selective supplement
Potassium Tellurite Solution – 1 % sterile solution for selective media
Potassium Tellurite Solution 1 % is a sterile supplement for selective media such as Vogel-Johnson Agar. Tellurite inhibits many bacteria and is reduced by staphylococci, which form black colonies.
- 1 % potassium tellurite, sterile
- 10 vials of 5 mL
- For Vogel-Johnson Agar and similar media
How Potassium Tellurite Solution works
Tellurite is toxic to most Gram-negative and many Gram-positive bacteria. Coagulase-positive staphylococci tolerate it and reduce it to metallic tellurium, so their colonies turn black. The solution is added to the sterile base after cooling, in the volume given by the medium formulation.
Technical data
| Concentration | 1 % potassium tellurite (50 mg per 5 mL vial) |
| Use | Add to the cooled sterile base in the volume given by the medium formulation |
| Storage | 2–8 °C |
| Shelf life | 2 years |
Applications and practical notes
Supplements and reagents complete the media and confirmation tests of the reference methods for coagulase-positive staphylococci, such as ISO 6888-1. Typical applications include:
- Preparation of Baird-Parker and similar selective agars
- Coagulase confirmation of suspect colonies
- Food, feed and pharmaceutical laboratories
- Routine and reference methods for staphylococci
Working with Potassium Tellurite Solution: Add the solution aseptically to base cooled to about 50 °C and mix well before pouring, because tellurite is not heat-stable in the complete medium.
Good practice with media and supplements: keep the bottle tightly closed in a cool, dry place, weigh the powder quickly to avoid moisture uptake, and use fresh distilled or deionised water. Check the pH of each new batch after preparation and before use, and label prepared media with the date. Performance of each lot can be verified with reference strains according to ISO 11133, the standard for the preparation, production, storage and performance testing of culture media.
About the Staphylococcus aureus methods: coagulase-positive staphylococci in the food chain are counted on Baird-Parker Agar according to ISO 6888-1, and typical colonies are confirmed with the coagulase test. For low numbers, ISO 6888-3 uses an MPN technique with Giolitti-Cantoni Broth, and the FDA BAM Chapter 12 describes direct plating and an MPN method with Tryptic Soy Broth containing 10 % NaCl. In pharmaceutical microbiology, the test for S. aureus in EP 2.6.13 and USP <62> uses Mannitol Salt Agar. COLO.Science offers media, supplements, rapid tests, identification kits and QC strains for every step.
Complete sets from one supplier: COLO.Science supplies culture media, supplements, rapid tests, identification kits and QC strains as complete sets for the method you follow. Send us your sample types and standards, and we will prepare an offer with the matching products and documentation.
Potassium Tellurite Solution is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include Potassium Tellurite Solution, please send us a request. With every delivery of Potassium Tellurite Solution you receive the lot number and expiry date, and on request we send the available documentation for Potassium Tellurite Solution.
Where Potassium Tellurite Solution fits in Staphylococcus aureus testing
- Colony count – Baird-Parker Agar with Egg Yolk Tellurite Emulsion (ISO 6888-1); alternatives: chromogenic S. aureus agar or Vogel-Johnson Agar
- Low numbers (MPN) – Giolitti-Cantoni Broth (ISO 6888-3) or Tryptic Soy Broth with 10 % NaCl (FDA BAM), then plating on Baird-Parker Agar
- Confirmation – coagulase test with Rabbit Plasma, latex kit or DNase Agar
- Pharmaceutical products – Mannitol Salt Agar for the S. aureus test of EP 2.6.13 / USP <62>; QC strains for media testing
See the complete Staphylococcus set in the Microbiology Catalogue →
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| Potassium Tellurite Solution 1% | PRO7746 | 10 × 5 mL |
Product notice: preparation, storage conditions and shelf life are given on the label. Technical data on this page are for orientation; the label and the lot documentation apply. B2B prices are quoted net, excluding VAT.
Sales and technical support
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Quotations and technical support for culture media and microbiology products across our international sales territory. B2B prices are net, excluding VAT.
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Send the sample type, target organism and the standard you follow. COLO.Science will put together the media, supplements, QC strains and confirmation tests for the whole procedure.
