BS ISO 20813:2019 pdf free.Molecular biomarker analysis – Methods of analysis for the detection and identification of animal species in foods and food products (nucleic acid-based methods)一General requirements and definitions.
4.4 Units of measurement Qualitative analyses indicate the presence or absence (lack of detection) of a certain target. In quantitative analyses, the measured value is calculated as ratio of DNA copy numbers (c/c). The use of this ratio should examine possible influences, including the number of DNA copies with regard to the target in the genome. Other units (e.g. ratio of masses) can be employed. The principles of calculation of the ratio shall be reported.
If a quantitative method is intended to judge the mass/mass ratio of different animal species ingredients in a sample, it should be indicated that the values measured for the DNA copy number ratio cannot reflect in all cases the mass/mass ratio of animal constituents in the sample. 4.5 ApplIcability When assessing if a method is fit for purpose, the following aspects regarding the nature of the target should he considered: — the location of the target (nuclear or mitochondrial); — the copy number per cell; — the length of the target sequence. For quantitative species-specific methods, a nuclear gene, excluding mitochondrial DNA shall be targeted. The target sequence shall be present as a single copy per haplold genome or the copy number shall be determined/known.The applicability of the method shall be tested by extracting DNA from test samples reflecting the matrices and analytical scope. DNA should be extracted from a minimum of three matrices of the most relevant types, including those types reflecting the method scope, containing a known mass/mass content of the target(s) species materials (evenly distributed over the percentage dynamic range of the method) and tissues relevant for the application. If sequence data are used for verification of animal speciation results, they should be based on appropriate databases with due consideration of the timing of submission of individual entries and any subsequent changes in taxonomic classification or naming. BS ISO 20813 pdf download.