DIN EN ISO 21571:2013-08

This International Standard provides general requirements and specific methods for DNA extraction/purification and quantitation. These methods are specified in the annexes. This International Standard has been developed for food, but could also be applicable, with some modifications, to feed and agricultural and environmental samples. The search for genetically modified origin of ingredients is performed by means of the following successive (or simultaneous) steps. After sample collection, nucleic acids are extracted from the test portion. Extracted nucleic acids can be further purified, simultaneously or after the extraction process. Afterwards, they are quantified (if necessary), diluted (if necessary) and subjected to analytical procedures, such as polymerase chain reaction, PCR. The objective of nucleic acid extraction methods is to provide nucleic acids suitable for subsequent analysis. The basic principle of DNA extraction consists of releasing the DNA present in the matrix and further, concurrently or subsequently, purifying the DNA from polymerase chain reaction (PCR) inhibitors. This Amendment contains a new procedure (guanidine chloroform method) for DNA extraction from soybean lecithins in raw and cold-pressed vegetable oils, respectively. The procedure has been validated in a collaborative trial involving 12 laboratories.