Staphylococcus aureus · Supplement for Baird-Parker Agar
Egg Yolk Tellurite Emulsion – supplement for Baird-Parker Agar, 1 × 200 mL
Egg Yolk Tellurite Emulsion completes Baird-Parker Agar Base for the enumeration of coagulase-positive staphylococci. The ready-to-use emulsion contains egg yolk and potassium tellurite. One 200 mL bottle completes 3.8 L of base, for laboratories that pour large batches.
- Ready-to-use egg yolk and tellurite
- 5 mL per 95 mL of base (5 % v/v)
- Pack: 1 × 200 mL
How Egg Yolk Tellurite Emulsion works
Egg yolk shows the lecithinase activity of S. aureus as an opaque zone and a clear halo around the colony. Potassium tellurite is selective and is reduced by staphylococci to black tellurium, which gives the typical black colonies.
Technical data
| Preparation | Add 5 mL of emulsion per 95 mL of sterile Baird-Parker Agar Base cooled to about 50 °C (5 % v/v), mix gently and pour plates |
| Composition | 30 % egg-yolk emulsion in saline with 1 % potassium tellurite |
| Storage | 2–8 °C |
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 Egg Yolk Tellurite Emulsion: Warm the emulsion to room temperature, shake gently and add it to base cooled to about 50 °C; do not reheat 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.
Egg Yolk Tellurite Emulsion is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include Egg Yolk Tellurite Emulsion, please send us a request. With every delivery of Egg Yolk Tellurite Emulsion you receive the lot number and expiry date, and on request we send the available documentation for Egg Yolk Tellurite Emulsion.
Where Egg Yolk Tellurite Emulsion 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 |
|---|---|---|
| Egg Yolk Tellurite Emulsion | PRO7741 | 1 × 200 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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Need the complete set for your method?
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.
