Staphylococcus aureus · Selective agar
Vogel-Johnson Agar – tellurite-mannitol agar for coagulase-positive staphylococci
Vogel-Johnson Agar is a selective and differential agar for the early detection of coagulase-positive, mannitol-fermenting staphylococci in food and pharmaceutical samples. Before use it is completed with potassium tellurite solution.
- Tellurite, lithium chloride and glycine for selectivity
- Black colonies on a yellow background = typical S. aureus
- Complete with Potassium Tellurite Solution 1 %
How Vogel-Johnson Agar works
Tellurite, lithium chloride and a high glycine content inhibit most of the accompanying flora. Coagulase-positive staphylococci reduce tellurite and form black colonies, and mannitol fermentation turns the phenol red indicator yellow around them. Colonies without a yellow zone are usually mannitol-negative staphylococci.
Typical colony appearance
| Organism | Colonies |
| S. aureus | Black colonies surrounded by a yellow zone |
| Mannitol-negative staphylococci | Black colonies, red medium |
| Gram-negative bacteria | Largely inhibited |
Applications and practical notes
Selective and differential agars for Staphylococcus aureus and other coagulase-positive staphylococci are used in food, feed, cosmetics and pharmaceutical testing, for example according to ISO 6888-1 and FDA BAM Chapter 12. Typical applications include:
- Enumeration of coagulase-positive staphylococci in food and feed
- Testing of dairy products, meat, ready meals and confectionery
- Microbial limit tests of non-sterile pharmaceutical and cosmetic products
- Hygiene monitoring of food handlers and surfaces
Working with Vogel-Johnson Agar: Add the tellurite solution only after the base has cooled to about 50 °C and confirm black colonies with the coagulase test.
Good practice with dehydrated media: 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.
Vogel-Johnson Agar is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include Vogel-Johnson Agar, please send us a request. With every delivery of Vogel-Johnson Agar you receive the lot number and expiry date, and on request we send the available documentation for Vogel-Johnson Agar.
Where Vogel-Johnson Agar 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 |
|---|---|---|
| Vogel-Johnson Agar | PRO7459 | 500 g |
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.
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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.
