Detection of genetically modified rice at the UK border - advice
Advice note prepared by Dr Michael Walker on behalf of the Government Chemist, regarding the detection of genetically modified rice at the UK border
Documents
Details
Background and further details
Acknowledgements and disclaimer
Introduction
There are currently no genetically modified rice or rice products authorised in the UK or European Union. However, there are reportedly genetically modified rice varieties that may be a source of contamination of rice or rice products. Commission Decision 2011/884/EU on emergency measures regarding unauthorised genetically modified rice in rice products originating from China (as amended) requires testing to be performed according to guidance published by the European Union Reference Laboratory for GM Food and Feed (EU-RL GMFF).
In recent years a series of technical appeals have been referred to the Government Chemist pursuant to Commission Decision 2011/884/EU. In these appeals Official Control Laboratory (Public Analyst) results were disputed on the basis of tests carried out by laboratories acting on behalf of the importers. On occasions the testing carried out on behalf of the importer has not followed the methods given in the EU-RL GMFF guidance. If the guidance is not followed there can be no grounds to challenge the Official Control Laboratory findings and it may not be a good use of public funds to embark on a referee analysis.
Advice
In order to assist importers and Port Health Authorities to follow the correct guidance we offer the following advice about the testing methods.
1) The EU-RL GMFF guidance is specific about the genetic elements that must be tested for and their associated methods. In brief (with further details below) these are:
- a. P-35S
- b. TNOS
- c. Cry1Ab/Ac
2) Importers instructing laboratories acting for them should ensure the above genetic elements are tested for by:
- a. Forwarding a link to this advice
- b. Asking their laboratory to follow the EU-RL GMFF guidance , and
- c. Asking their laboratory to complete the attached questionnaire:
3) A valid referral to the Government Chemist can usually only proceed if the importer can provide:
- a. A certificate of analysis for the consignment containing negative results for P-35S, T-NOS, Cry1Ab/Ac,
- b. Positive results for a rice taxon-specific method, e.g. PLD,
- c. The completed questionnaire on methods of analysis.
- d. See also Submit a referee sample and Submit a supplementary expert opinion sample
4) This note must be read in conjunction with the EU-RL GMFF guidance.
Background and further details
There are no genetically modified rice or rice products authorised in the UK or the European Union. However, there are reportedly genetically modified rice varieties that may be a source of contamination of rice products imported from China. Relevant details of their molecular structure and DNA sequence information are not currently officially available and consequently normally recommended specific methods of analysis are not sufficient to detect all possible genetically modified rice varieties.
Therefore, Commission Decision 2011/884/EU as amended requires tests to be performed according to guidance published by the European Union Reference Laboratory for GM Food and Feed (EU-RL GMFF). The tests look for a range of genetic modifications and consist of real-time polymerase chain reaction (PCR) assays for at least the following genetic elements: DNA sequences characteristic for the 35S promoter derived from Cauliflower Mosaic Virus (P-35S), the nopaline synthase terminator (T-NOS) derived from Agrobacterium tumefaciens and the genetically engineered Cry1Ab/Ac. In addition, a rice taxon specific method should be used: the phospholipase D (PLD) gene target is recommended.
The assays are P-35S, T-NOS and Cry1Ab/Ac SYBR® Green intercalating DNA binding dye real-time PCR methods including determination of the melting temperature (Tm) (dissociation) of the double stranded PCR product (melt curve) or a Taqman® P-35S/T-NOS duplex fluorogenic probe real-time PCR method. Please note however that Page 7 of the EU-RL GMFF guidance and Annex II to Commission Decision 2011/884/EU (consolidated text https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1589297163560&uri=CELEX:02011D0884-20130704 ) specify a SYBR® green assay for Cry1Ab/Ac is required.
Official Control (Public Analyst) laboratories work to the EU-RL GMFF guidance.
Some commercial laboratories may offer a variety of specific methods or generic screening for GMOs. While these analyses are appropriate in many situations they may not be applicable to rice and rice products pursuant to the relevant legislation. If the wrong methods are used by the importer’s laboratory there are no grounds to dispute the Official Control (Public Analyst) Laboratory result. If the importer’s laboratory carries out the correct method it will either:
(a) Confirm the Official Control (Public Analyst) Laboratory result in which case the consignment is non-complaint and cannot enter the UK,
OR
(b) Produce a properly carried out result contrary to that of the Official Control (Public Analyst) Laboratory in which case the Government Chemist is empowered to carry out referee case to decide the issue. In some instances, after careful investigation, the Government Chemist has confirmed the Official Control (Public Analyst) laboratory findings that a GM motif was present, in other instances we have confirmed the findings of the laboratory acting for the importer that no GM motif was found.
The following examples explain more fully some common situations where laboratories acting for the importer have not carried out the appropriate tests. Please note, we are not impugning importer’s laboratories abilities to carry out GMO testing in general, but that in some instances the specific EU-RL GMFF guidance has not been followed.
Examples illustrating the guidance has not been followed
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One or more of the required genetic elements (P-35S, T-NOS or Cry1Ab/Ac) has not been tested for.
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An event-specific rather than a wider assay has been used. An example is using an assay specifically for the GMO ‘Bt63 rice’. This GMO contains genetic elements inclusive of Cry1Ab/Ac but an event-specific test for Bt63 rice will only detect this particular GMO variety and would not provide information on the possible presence or absence of Cry1Ab/Ac or other genetic elements. It is thus not sufficiently wide to encompass the requirements of the EU-RL GMFF guidance on other GMOs containing Cry1Ab/Ac.
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The correct (SYBR® green) assay has not been used for Cry1Ab/Ac (see above).
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The PLD assay is missing. PLD refers to the rice-specific phospholipase D gene target sequence. Analysis for this genetic element is recommended in the EU-RL guidance and serves to ensure that the sample does indeed contain rice as well as serving as a check on PCR efficiency. Inclusion of a PLD assay may be noted as such in a laboratory report or may be inferred from a statement such as “Sample Specific LOD (rice) [Real-time PCR] …”. Further details are in the EU-RL GMFF guidance on pages 5 – 7, Table 1 and Figures 1 and 2 (pages 13 & 14).
ISO/IEC 17025 Accreditation
We have had some enquiries about accreditation to ISO/IEC 17025 for methods for testing for GM rice from China, however this is a somewhat grey area. The EU-RL GMFF guidance specifically notes (page 4) that “ … laboratories accredited under ISO/IEC 170255 cannot include related test procedures into the scope of their accreditation”. This is because of the lack of exact knowledge of what the GM event(s) might be, lack of (certified) reference materials, and lack of proficiency tests to assess the performance of laboratories. It is required that the analytical results obtained are of the highest possible quality and that control laboratories use the same, or identical analytical procedures detailed in the EU-RL GMFF guidance.
The laboratory should of course have a fully documented and validated method including appropriate management and quality control procedures. It is possible to achieve ISO/IEC 17025 accreditation for the procedures recommended in the EU-RL GMFF guidance however there are few if any laboratories in the UK with this accreditation. The Government Chemist therefore advises that in choosing a laboratory to carry out analysis an importer of rice or rice products from China should select a laboratory that:
- Has demonstrable expertise and experience in GMO analysis (for example by possessing ISO/IEC 17025 accreditation in this general area, or specific accreditation in relation to the EU-RL GMFF guidance)
- And undertakes to work to and report against the EU-RL GMFF guidance.
Use of the term ‘screening’
The EU-RL GMFF guidance talks about ‘screening tests’. Typical laboratory practice would be to follow up a ‘screening test’ with a ‘confirmatory test’. However, properly carried out the assays recommended in the EU-RL GMFF guidance contain adequate safeguards to render them sufficient in themselves without the need for any further confirmatory work. In a referee case the Government Chemist team apply strict adherence to the EU-RL GMFF guidance and sufficient investigation and replication to give optimal confidence to our results.
Acknowledgements and disclaimer
This advice was prepared by Dr Michael Walker MChemA on behalf of the Government Chemist, if you have any questions about this advice please contact michael.walker@lgcgroup.com. Helpful and expert input is acknowledged from Dr Malcolm Burns, Kirstin Gray and Paul Hancock MChemA.
‘Any view, information or advice given by LGC, the Laboratory of the Government Chemist, is formulated with care, but is based necessarily upon the information and data provided to it as part of the enquiry. If the advice herein was prepared with the aid of review of the readily available literature it is not claimed to be comprehensive. No responsibility can be taken for the use made of any view, information or advice given, whether by the enquirer or a third party. In particular, any view, information or advice given should not be taken as an authoritative statement or interpretation of the law, as this is a matter for the courts.’