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The certification of a reference material for the evaluation of the ISO method for the detection of Salmonella
Author(s) -
Veld P.H. in't,
Van StrijpLockefeer N.G.W.M.,
Havelaar A.H.,
Maier E.A.
Publication year - 1996
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1996.tb03248.x
Subject(s) - salmonella , enumeration , certified reference materials , detection limit , homogeneity (statistics) , certification , mathematics , confidence interval , chromatography , materials science , statistics , chemistry , biology , bacteria , combinatorics , genetics , law , political science
A reference material (RM) containing Salmonella typhimurium was certified as CRM 507 by the Standards, Measurements and Testing Programme of the European Commission. The material consists of a gelatin capsule filled with artificially contaminated milk powder. The material is certified for the evaluation of presence/absence methods based on the ISO 6579 procedure for the detection of Salmonella. In the certification study 11 laboratories determined the presence/absence of Salmonella from each of 50 capsules. They also determined the mean number of colony‐forming particles (cfp) and the homogeneity of the batch of RM according to an enumeration procedure. Certified values were calculated for both procedures separately. Based on the presence/absence procedure a fraction of capsules in which no Salmonella could be detected of 2·7% (one‐sided 95% confidence upper limit 4·4%) was certified, for the enumeration procedure this fraction was 0·61% (one‐sided 95% confidence upper limit 1·6%). The certified mean number of Salmonella cfp in one capsale is 5·9 (two‐sided 95% confidence interval 5·3—6·4). Data on the preparation, identification, stability (at storage and higher temperatures) and homogeneity of the material are presented.