| Reprinted with permission from the Australian Oilseeds Federation:
Testing Protocol 23 August 2005
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Investigation of the source of the adventitious presence of genetically modified (GM) material in a consignment of canola from Victoria
Background
A consignment of canola from storages in Victoria was tested for the presence of genetically modified (GM) material.
A very low level of GM material was identified as Bayer CropScience’s (Bayer) Topas 19/2 event of the pat gene, on 9 July 2005. The level detected was determined to be in the order of 0.01%.
As this event is approved by the OGTR for release into the environment in Australia, and by FSANZ for use in food, there are no federal regulatory issues.
However, Victoria’s Control of GM Crops Act (2004) prohibits the commercial cultivation of OGTR approved Bayer GM canola lines, including the Topas 19/2 event in the State.
In response to the above detection, the Australian Oilseeds Federation (AOF) has offered to undertake an investigation into the source of the material.
The AOF Taskforce
The AOF in association with the Australian Seeds Federation (ASF) have formed a taskforce to undertake the investigation. The taskforce membership includes:
• Rosemary Richards, Australian Oilseeds Federation (Chair)
• Chris Melham, Australian Seeds Federation
• Graeme Smith, Pacific Seeds
• Phil Salisbury, University of Melbourne
An independent expert, Jim McDonald, has been contracted by the AOF to provide technical expertise in developing and overseeing the testing protocols. The OGTR will provide expert technical comment on proposed testing protocol. Peter Whitehouse, Bayer CropScience, will also be involved as required to provide technical input.
Terms of Reference
1. To assess and prioritise options for the identification of the possible source(s) of the Topas 19/2 GM material.
2. To develop testing protocols to rapidly identify the source of the Topas 19/2 material.
3. To provide advice in relation to the likely extent of Topas 19/2 material in commercial crops and storages in Victoria, and elsewhere in Australia.
4. To provide advice for options for remedial actions for existing crops and storages and further management arrangements.
Australian Oilseeds Federation
Protocol
23 August 2005
Testing Protocol 23 August 2005
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Options for the source of the Topas 19/2 GM material
Potential Source Commentary Likelihood
1. The Bayer Crop Sciences Field Trials of GM canola Topas 19/2 has only been grown in small scale field trials in Tasmania, and only in 1998. Direct contamination of grain crops in Victoria can therefore be ruled out. Pollen flow from these trials to seed production of a variety being increased for sale in Victoria remains an unlikely possibility, as does physical contamination from planting or harvest equipment used on the field trial site and later used for a seed increase block.
Incursion into seed crops in Tasmania is considered less likely because of the isolation and hygiene requirements of the trial permits and the fact that Tasmania is not commonly used for contra season canola increases.
Unlikely
2. Escape into conventional germplasm of the breeding program of Bayer’s Seed Partner breeding programs
The records show that these programs were not using Topas 19/2.
Unlikely
3. Inadvertently imported through breeding material from North America
Events containing the pat gene including Topas 19/2 have been commercialised in Canada and were first used in field trials in 1990.
Likely
4. Imported in commercial or parent seed from North America
It is believed most companies importing parent seed test for purity, but it remains a possibility that the GM material was below the limits of detection, or the import occurred before routine testing was introduced.
Likely
5. Seed import of a variety carrying the gene, either deliberately for use as seed, or lodged in imported farm machinery
This is considered unlikely, Canadian varieties are poorly adapted to Australian conditions and it appears likely deliveries from more than one farmer contributed to the occurrence.
Unlikely
6. Seed imports of pasture species containing canola as a contaminant or GM material in imported forage rape planting seed.
This remains a possibility but since the Canadian varieties are poorly adapted it is unlikely they will survive in sufficient numbers to explain the occurrence.
Unlikely
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Test methods
Testing is currently based on two methods:
a. Grow out tests - In this procedure, seed is sown into soil in a glasshouse or field
depending on scale of testing. After the seedlings emerge, they are sprayed 2-3 times
from 2-3 leaf stage with high rates of the Bayer herbicide (Basta). Any seedlings that survive are potentially GM. PCR tests will confirm that these are GM and not herbicide escapes. Because this test allows large numbers of seeds to be tested it increases the possibility of a detection.
b. Polymerase Chain Reaction (PCR) – a highly sensitive laboratory test based on the use of gene sequences specific to the gene event (Topas 19/2) under examination (these gene sequences are termed ‘event specific primers’ and are required to be licenced for use by Bayer). This test can detect traces down to approximately 0.001% when working with pure samples. However, crushed seed samples contain impurities that reduce sensitivity. The accuracy of the test in practice is outlined in the table below. This test is also expensive.
Sample security
The samples will be drawn following International Seed Testing Procedures and coded by Jim McDonald prior to shipment to the Testing Lab to ensure the laboratory is unaware of the identity of any particular sample.
The testing will be done by Eurofins, the European testing lab (an independent, accredited testing laboratory) who confirmed the presence of the Topas 19/2 in the original grain sample.
Eurofins has International Standards Organization accredited procedures and participates in various proficiency or referee testing procedures including the USDA’s and those of the UK
Food Standards Agency and FAPAS (UK Dept of Environment Food and Rural Affairs).
The Topas 19/2 event specific testing system has been provided by Bayer Crop Sciences, as it was for the original test on the grain sample.
Tests - accuracy and confidence
Given that the level of the adventitious presence (AP) in stocks of seed is likely to be very low and the possibility of false positives using the PCR test, the most appropriate test to use initially, is the grow out test.
Sample Size
The sample size affects the confidence levels and accuracy of the tests.
Some relevant tolerances and test numbers are shown in the following table reproduced from The American Seed Trade Association (ASTA) paper “Standardization of Seed Testing Protocols for Adventitious Presence”:
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Confidence Level (%) AP Purity Standard No. Seeds to be tested
95 1.0 300
0.5 600
0.1 3000
0.01 30000
99 1.0 460
0.5 1000
0.1 4600
0.01 46000
100 0.0 All Seed
The standard international practice for testing batches of seed is to use 3000 seeds per test, which provides 95% confidence level at the 0.1% AP Purity Standard
Proposed testing protocol
Primary test
The most effective and rapid approach is to first test the bulk storage from which the grain consignment was derived. Grain from the consignment will be tested via ‘grow out tests’ under secure and controlled conditions. This will mean hundreds of thousands of seeds will be grown to provide a high likelihood that any GM material present will be selected (ie: batched lots each of 46,000 seeds will provide a 99% confidence limit of detecting trace amounts of GM seed at the 0.01% AP level).
The surviving seedlings will be transplanted from the field and genetically profiled to identify the parent variety.
Backup test
As a back-up test, the Standard International Protocol will be used to test batches of seed provided by companies and breeders (ie: batches of 3,000 seed lots will provide a 95% confidence level of detecting GM material at the 0.1% AP Purity Standard).
Seed samples will be provided by breeders or the trade.
Samples from the grain consignment have been provided. Grain batches will be collected and dealt with according to the testing protocols.
Independent, accredited testing laboratories will conduct the proposed testing protocol.
Processes, overseen by Jim McDonald, will ensure samples are coded and so are not identified to the testing agency.
Endorsement
DPI (Victoria) and industry have endorsed this protocol for the investigation of the source of the adventitious presence of GM material in a consignment of canola from Victoria . |
