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FP7

Certification of a reference material with Escherichia coli O157 (NCTC 12900) at a level of 4 colony forming units per material sphere, IRMM-351

Funded under: FP7-JRC

Abstract

This report describes the certification of a reference material (IRMM-351) of Escherichia coli O157. Certified Reference Materials (CRMs) for microbiological analysis are indispensable tools for development and validation of detection methods and for the implementation and support of internal and external quality control in the area of microbiological analysis. Each vial contains one material sphere of E. coli O157. The homogeneity and stability (at 4 Degree Celsius, -20 Degree Celsius and -70 Degree Celsius) of the batch was assessed by monitoring colony forming units (cfu) on nutrient agar (NA) and enterohemolysin agar (EhlyA) of selected vials by colony counting. The material is not stable at 4 Degree Celsius but no instability was detected when stored at -20 Degree Celsius for up to 12 months and at -70 Degree Celsius for up to 54 months. The batch was characterised by six laboratories to determine a certified value of cfu per vial on NA and EhlyA. The certified value is 4 cfu on both agars with an expanded uncertainty of 2 using a coverage factor k = 2, corresponding to a level of confidence of about 95%. DNA sequence analysis of the coding region for the fliC gene identified the material as E. coli O157.

Additional information

Authors: DE BAETS L, European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel (BE);VAN IWAARDEN P, European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel (BE);BREMSER W, European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel (BE);MEEUS N, European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel (BE);PHILIPP W, European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel (BE);SCHIMMEL H, European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel (BE)
Bibliographic Reference: EUR 23540 EN (2008), 35 pp. Free of charge
Availability: Available from European Commission, JRC Knowledge Management Unit, Ispra (IT) Tel: +39 033278 9893 Fax: +39 033278 5409 E-mail: jrc-info@ec.europa.eu or Bruxelles (BE) Tel: +32 2 295 76 24 Fax: +32 2 299 63 22
ISBN: ISBN: 978-92-79-10271-4
Record Number: 200910170 / Last updated on: 2009-02-26
Category: PUBLICATION
Original language: en
Available languages: en
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