BS ISO 21187 pdf download Milk — Quantitative determination of bacteriological quality — Guidance for establishing and verifying a conversion relationship between routine method results and anchor method results
This International Standard gives guidelines for the establishment of a conversion relationship between theresults of a routine method and an anchor method, and its verification for the quantitative determination of thebacteriological quality of milk.
2 Normative references
The following referenced documents are indispensable for the application of this document. For datedreterences. only the edition cied applies For undated relerences. the latest edition of the reterenceddocument (including any amendments) applies.
ISO 3534-1, Statistics — Vocabulary and symbols – Part 1: Probability and general statistical terms
ISO 8196-1 IDF 128-1, Mik Definition and evaluation of the overall accuracy of indirect methods of milkanalysis – Part 1: Analytical attributes of indirect methods
ISO 8196-2 IDF 128-2, Milk Definition and evaluation of the overall accuracy of indirect methods of milkanalysis — Part 2: Calibration and quality control in the dairy laboratory
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3534-1, ISO 8196-1 IDF 128-1.
ISO 8196-2 IDF 128-2 and the following apply.
method of analysis allowing quantification of the bacteriological status of a test sample
NOTE 1The method can be proprietary or non-commercial.
NOTE 2The term “routine or “alternative” in this international Standard refers to the entire method. lt includes allaspects (such as sample pretreatment, materials and instruments) required for the execution of the method
NOTE 3The term “routine method” is used in this International Standard.
method of analysis internationally recognized by experts or by agreement between parties, and used, forinstance, in legislation when expressing official limits for bacteriological quality
NOTEit is stressed that,in quantitative microbiology, any obtained value is only defined by the method descriptiorapplied. This applies to any routine method as well as, for instance, to the standard plate count for the enumeration ofmicroorganisms. For the purpose of conversion, the term anchor method is preterred over the term reterence method andtherefore is used throughout this International Standard.
component or property which is measured by the method of analysis
NOTEThe analyte may be the microorganism, stained particles (e.g. microscopic count), components otmicroorganisms (e.g. lipopolysaccharides), the result of their ability to multiply (e.g. colony-forming units) or their metabolicactivity (e.g.change in conductivity/impedance).
laboratory, possibly appointed by the competent authorities, having the qualified staff and skils to organize, tocoordinate and to report on the outcome of the activities for the establishment or the maintenance of aconversion relationship
For establishing and verifying a conversion relationship between the results of a routine method and theanchor method, the following prerequisites apply.
The routine method should have been validated according to ISO 16140. Procedures for sampling, test
asample preservation, sample transport, sample storage, sample pre-treatment, analysis and calculation otresults should be documented, strictly standardized and controlled in agreement with ISO/IEC 17025EA-4/10,or comparable standards.
6The anchor method should have been validated, documented,strictly standardized and controlled inagreement with ISO/IEC 17025, EA-4/10 or comparable standards
The protocol for the establishment of the conversion relationship and its verification should beCdocumented. lt should follow the guidelines of this International Standard. Approval by competentauthorities should be sought where the final aim is that results from a routine method are to be judgedagainst official limits stated in the anchor method units.