ISO 21571:2005 pdf download.Foodstuffs -Methods of analysis for the detection of genetically modified organisms and derived products —Nucleic acid extraction.
DNA extractions shall be carried out at least on two test portions.
Storage of standards, samples and test portions shall comply with ISO 24276 and shall be organized in such a
way as to preserve the biochemical parameters to be analysed (for details, see lSO/IEC 17025).
5.1.2 Samples
All operations for the preparation of test samples (e.g. grinding, homogenization, division, drying) shal be camed out in accordance with the procedures described in ISO 24276, taking care to prevent all contamination of the sample or modification of its composition.
Laboratory samples shall be sufficiently homogeneous before reduang the laboratory sample and taking the test portion,
For liquid samples, shake the vessel containing the sample to improve the homogenization of the product. In the case of non-homogenous products like raw oils, check that the sediments have been completely removed from the walls of the vesset
For solid matrices that cannot easily be suspended, the matrix shall be ground to reduce the particle size aridior facilitate the extractability of DNA. In such a case, attention shaM be paid to the particle size. The test portion subØcted to extraction shall contain a minimum number of particles as specitled in ISO 21568 Milling/grinding devices should be capable of being thoroughly cleaned and shall be selected in order to achieve the expected particle number and particle size distribution within the test portion as defined in
ISO 21568.
If components of the laboratory sample have been removed poor to extraction, then such procedures shall be reported.
Final food products that are solid or paste and have high lipid contents are often not easy to grind to the desired particle size in a single step. Several procedures may therefore be added, such as lipid removal using hexane after intermediate grinding, freezing or freeze-drying before grinding.
Storage of standards, samples and test portions shall comply with ISO 24276 and shall be organized in such a
way as to preserve the biochemical parameters to be analysed (for details, see lSO/IEC 17025).
5.1.2 Samples
All operations for the preparation of test samples (e.g. grinding, homogenization, division, drying) shal be camed out in accordance with the procedures described in ISO 24276, taking care to prevent all contamination of the sample or modification of its composition.
Laboratory samples shall be sufficiently homogeneous before reduang the laboratory sample and taking the test portion,
For liquid samples, shake the vessel containing the sample to improve the homogenization of the product. In the case of non-homogenous products like raw oils, check that the sediments have been completely removed from the walls of the vesset
For solid matrices that cannot easily be suspended, the matrix shall be ground to reduce the particle size aridior facilitate the extractability of DNA. In such a case, attention shaM be paid to the particle size. The test portion subØcted to extraction shall contain a minimum number of particles as specitled in ISO 21568 Milling/grinding devices should be capable of being thoroughly cleaned and shall be selected in order to achieve the expected particle number and particle size distribution within the test portion as defined in
ISO 21568.
If components of the laboratory sample have been removed poor to extraction, then such procedures shall be reported.
Final food products that are solid or paste and have high lipid contents are often not easy to grind to the desired particle size in a single step. Several procedures may therefore be added, such as lipid removal using hexane after intermediate grinding, freezing or freeze-drying before grinding.
