Salmonella detection · Step 3 – selective isolation
Hektoen Enteric Agar – selective plating medium for Salmonella and Shigella
Hektoen Enteric (HE) Agar is a selective and differential plating medium for the isolation of Salmonella and Shigella from food and pharmaceutical samples. It is used after selective enrichment, as a second agar next to XLD Agar.
- Salmonella: blue-green colonies with black centres
- Used in ISO, USA FDA and USP methods
- Dehydrated powder, 500 g bottle · COLO code PRO7441
How Hektoen Enteric Agar works
Bile salts inhibit Gram-positive and many Gram-negative accompanying bacteria. Bacteria that ferment lactose, sucrose or salicin form orange to salmon-pink colonies, while non-fermenters such as Salmonella and Shigella remain blue-green. Thiosulfate and ferric ammonium citrate show hydrogen sulfide production as black colony centres.
Typical colony appearance
| Organism | Colonies |
| Salmonella | blue-green, with black centres |
| Shigella | blue-green, without black centres |
| Lactose / sucrose fermenters | orange to yellow |
Technical data
| Preparation | 90.8 g per litre of water; heat to boiling to dissolve, do not autoclave; cool to 48 ± 2 °C and pour plates |
| Final pH | 7.5 ± 0.2 |
| Incubation | 36 ± 1 °C, 18–24 h |
| Storage | Dry, dark place; close the cap tightly after use |
| Shelf life | 3 years unopened |
Applications and practical notes
Hektoen Enteric Agar is a plating medium in the FDA BAM Chapter 5 procedures and is often used as a second agar next to XLD. Typical applications include:
- meat, poultry, eggs and egg products
- milk, dairy products and infant formula
- feed, spices and dry foods
- environmental swabs from the food production area
Working with Hektoen Enteric Agar: Do not autoclave the medium and avoid prolonged heating. Plates are incubated inverted and read after 18–24 h; typical colonies are confirmed biochemically and serologically.
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 Salmonella culture method: the reference method for Salmonella in the food chain, ISO 6579-1, has four steps: non-selective pre-enrichment, selective enrichment in two broths, plating on two selective agars and confirmation of typical colonies. The FDA BAM Chapter 5 follows the same principle with media adapted to different food types. Rapid tests and identification kits shorten the time to result, but positive screening results are usually confirmed by the culture method. COLO.Science offers products for every step, so that one supplier covers the whole procedure.
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.
Hektoen Enteric 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 Hektoen Enteric Agar, please send us a request.
Where Hektoen Enteric Agar fits in the Salmonella workflow
- Pre-enrichment – Buffered Peptone Water or Lactose Broth
- Selective enrichment – RVS Broth and MKTTn Broth
- Selective isolation – XLD Agar plus a second selective or chromogenic agar
- Confirmation – TSI, Lysine Iron Agar, Urea Agar, latex and biochemical identification
See the complete Salmonella set in the Microbiology Catalogue →
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| Hektoen Enteric Agar, dehydrated | PRO7441 | 500 g |
| XLD Agar, dehydrated | PRO7437 | 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.
Sales and technical support
COLO LabExperts
Polje ob Sotli 4, SI-3255, Slovenia
Quotations and technical support for culture media and microbiology products across our international sales territory. B2B prices are net, excluding VAT.
COLO.SCIENCE | MICROBIOLOGY SUPPORT
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.
