Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 16, Horizontal methods for molecular biomarker analysis.

This second edition cancels and replaces the first edition (ISO 21569-6:2016), which has been technically revised.

The main changes are as follows:

in 8.2 and Table 5 , “C_t” and “C_p” have been replaced by "C_q";
the Bibliography has been revised to correct a bibliographic reference.

A list of all parts in the ISO 21569 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

1 Scope

This document specifies a procedure for the detection of a DNA sequence of the modified cry1Ab/Ac gene and a procedure for the detection of the DNA transition sequence between the maize ubiquitin promoter (Pubi) and the cry1Ab/Ac gene. The modified cry1Ab/Ac gene and the Pubi-cry construct are frequently found in genetically modified Bt (Bacillus thuringiensis) plants. Both detection methods are based on real-time PCR and can be used for qualitative screening purposes. For identification and quantification of a specific genetically modified plant (event) a follow-up analysis has to be carried out.

This document is applicable to the analysis of DNA extracted from foodstuffs. It can also be suitable for the analysis of DNA extracted from other products such as feedstuffs and seeds. The application of these methods requires the extraction of an adequate amount of amplifiable DNA from the relevant matrix.

2 Normative references

3 Terms and definitions

4 Principle

5 Reagents and materials

5.1 General

5.2 PCR reagents

6 Apparatus

6.1

7 Procedure

7.1 Preparation of test samples

7.2 Preparation of DNA extracts

7.3 PCR setup

7.4 Temperature-time programme

8 Accept/reject criteria

8.1 General

8.2 Identification

9 Validation status and performance criteria

9.1 General

9.2 Robustness

9.3 Collaborative trial

9.4 Sensitivity

9.5 Specificity

10 Test report

Bibliography