E. coli · QC reference strain
E. coli O157 QC Strain – reference strain for media testing
Escherichia coli O157:H7 NCTC 12900 is a non-toxigenic reference strain for quality control of O157 media, latex tests and PCR methods. It shows the typical O157 reactions without producing Shiga toxins.
- Lyophilised, single use
- For growth-promotion and positive controls
- Rehydration fluid included
How E. coli O157 QC Strain is used
The lyophilised culture is rehydrated, spread on a non-selective plate and used to check SMAC, chromogenic O157 agar, latex and PCR kits.
Technical data
| Preparation | Add 1.0 mL supplied recovery fluid, vortex; spread 0.1 mL on non-selective plate or into broth |
| Incubation | Most bacteria 36 ± 1 °C 24-48 h; moulds/yeasts 26 ± 1 °C 2-5 d; Campylobacter 42 °C microaerophilic; clostridia anaerobic 48-96 h |
| Storage | Per label; opened/unused and reconstituted at 2-8 °C, use reconstituted within 8 h |
Applications and practical notes
Reference strains of E. coli are used for growth-promotion and selectivity testing of culture media according to ISO 11133 and for positive controls in routine methods. Typical applications include:
- Growth-promotion testing of new media lots
- Positive controls for coliform and E. coli methods
- Proficiency and method-verification studies
- Pharmacopoeial microbial limit tests
Working with E. coli O157 QC Strain: Record the passage number and use the strain as a positive control in each O157 run.
Good practice with rapid tests: store the kit as stated on the label, let the components reach room temperature before use and use each item only once. Record the lot number and the result, and confirm positive results according to the reference method when this is required.
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.
E. coli O157 QC Strain is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include E. coli O157 QC Strain, please send us a request. With every delivery of E. coli O157 QC Strain you receive the lot number and expiry date, and on request we send the available documentation for E. coli O157 QC Strain.
Where E. coli O157 QC Strain fits in coliform and E. coli testing
- Presumptive test – Lauryl Sulfate Tryptose Broth (MPN) or VRBL / chromogenic agar (colony count)
- Confirmation – BGLB Broth for coliforms; EC or EC-MUG Broth at 44.5 °C for E. coli
- Isolation – EMB, MacConkey, TBX or chromogenic E. coli agar
- Identification – IMViC kit; for O157 and STEC: SMAC or chromogenic O157 agar, latex and PCR
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| E. coli O157 QC Strain NCTC 12900 | PRO7843 | 1 vial |
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.
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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.
