Cronobacter · Selective enrichment
Modified Lauryl Sulfate Tryptose Broth – selective enrichment of Cronobacter
Modified Lauryl Sulfate Tryptose Broth (mLST) is a selective enrichment broth for Cronobacter spp. in infant formula and other dry foods. With the mLST Broth Supplement it suppresses Gram-positive bacteria, and incubation at 44 °C favours Cronobacter.
- Selective enrichment of Cronobacter
- Complete with mLST Broth Supplement
- Incubation at 44 °C
How Modified Lauryl Sulfate Tryptose Broth works
Tryptose provides nutrients and lactose a fermentable sugar, while a high sodium chloride content and sodium lauryl sulfate inhibit many accompanying bacteria. The glycopeptide supplement added after cooling suppresses Gram-positive flora. After enrichment, the broth is streaked on Chromogenic Cronobacter Agar.
Typical results
| Organism | Result |
| Cronobacter sakazakii | Growth; blue-green colonies on the subsequent chromogenic agar |
| Enterococcus faecalis | Inhibited |
Technical data
| Preparation | 64.6 g/L; boil to dissolve, autoclave 121 °C 15 min; cool to about 30 °C and add one vial of mLST Broth Supplement per 100 mL |
| Final pH | 6.8 ± 0.2 |
| Incubation | 44 ± 0.5 °C, 24 ± 2 h |
| Storage | Dry, dark place; keep the container tightly closed |
| Shelf life | 3 years unopened |
Applications and practical notes
Cronobacter spp. (formerly Enterobacter sakazakii) can cause severe infections in newborns, so powdered infant formula and its production environment are tested according to ISO 22964. Typical applications include:
- Powdered infant formula and follow-on formula
- Infant cereals and milk powders
- Environmental samples from dry production areas
- Ingredients for infant foods
Working with Modified Lauryl Sulfate Tryptose Broth: Add the supplement only after the broth has cooled to about 30 °C, and transfer 0.1 mL of the pre-enrichment into 10 mL of complete broth.
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 Cronobacter method: ISO 22964 is the horizontal method for Cronobacter spp. in infant formula, infant cereals, milk powders and production environments. It combines pre-enrichment in Buffered Peptone Water, selective enrichment at 41.5 °C, plating on a chromogenic agar and biochemical confirmation; the FDA BAM Chapter 29 uses a similar culture and PCR approach. COLO.Science offers media, supplements, rapid tests and identification kits 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.
Modified Lauryl Sulfate Tryptose Broth is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include Modified Lauryl Sulfate Tryptose Broth, please send us a request. With every delivery of Modified Lauryl Sulfate Tryptose Broth you receive the lot number and expiry date, and on request we send the available documentation for Modified Lauryl Sulfate Tryptose Broth.
Where Modified Lauryl Sulfate Tryptose Broth fits in Cronobacter testing
- Pre-enrichment – Buffered Peptone Water, 34–38 °C
- Selective enrichment – Cronobacter enrichment broth with vancomycin-type supplement at 41.5 °C
- Isolation – Chromogenic Cronobacter Agar: blue-green colonies
- Confirmation – biochemical identification; rapid screening by qPCR, LAMP or detection plate
See all Cronobacter products in the Microbiology Catalogue →
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| Modified Lauryl Sulfate Tryptose Broth (mLST) | PRO7454 | 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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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.
