ISO 16297:2020 pdf download

ISO 16297:2020 pdf download.Milk — Bacterial count — Protocol for the evaluation of alternative methods
1 Scope
This document specifies a protocol for the evaluation of instrumental alternative methods for total bacterial count in raw milk from animals of different species.
NOTE The document is complementary to ISO 16140-2 and ISO 8196 | IDF 128 (all parts).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results — Part 1: General principles and definitions
ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method
ISO 8196 | IDF 128 (all parts), Milk — Definition and evaluation of the overall accuracy of alternative methods of milk analysis
ISO 16140-1, Microbiology of the food chain — Method validation — Part 1: Vocabulary
ISO 21187 | IDF 196, Milk — Quantitative determination of bacteriological quality — Guidance for establishing and verifying a conversion relationship between results of an alternative method and anchor method results
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5725-1, ISO 5725-2,
ISO 8196-1 | IDF 128-1, ISO 8196-2 | IDF 128-2, ISO 8196-3 | IDF 128-3 and ISO 16140-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Transformation of results
A prerequisite for statistics most common in the evaluation of measuring methods is the approximation of a normal distribution of the data. The exponential multiplication of microorganisms usually leads to a right-tailed distribution with quantitative microbiological parameters. Thus, in general, transformation of the raw data is necessary for approximation of normality. This is usually a common logarithmic transformation. The most appropriate transformation can be checked by comparing histograms. All statistics are then computed from the transformed data, unless specified otherwise, and only the final results are re-transformed to give a more expressive idea of the situation to the user (see Reference [2]).
5 Attributes of the alternative method
5.1 General
For each alternative method, only the relevant parameters outlined in this clause shall be evaluated.For example, the measuring range (see 5.3) of the plate loop method is determined by the loop(s) used and the determination of the parameter is not relevant.