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Thursday 7 August 2003
For more corn to grow there has to be viable corn seeds or corn vegetation
which can sprout into new plants. No evidence of corn seed or volunteer plant
growth was seen either within the fields or within 3 metres around the perimeter
of the fields.
Each of the four fields in Gisborne had visual inspections conducted by MAF.
These inspections consisted of systematic walking 'sweeps' of the fields
using four-person teams, which entirely covered each field. Inspectors were
looking for evidence of corn seed, remaining corn vegetation (stubble) or growth
of volunteer corn plants. The field teams reported a high level of confidence
that nothing was missed, due to good visibility of the ground.
In addition, a leading New Zealand scientist at Crop and Food Research,
specialising in maize and sweet corn breeding and growing, has provided MAF with
recommendations that specifically relate to the control of volunteers in sweet
corn fields. Based on this advice MAF considers that the four fields have been
subjected to post-harvest cultivation treatments that would prevent any viable
material remaining in the fields. Harvesting also occurs when the kernels are
physiologically immature and therefore non-viable.
The other fields throughout New Zealand will be managed by a site management
plan that will address a range of potential scenarios and risk. The initial
indications are that many sweet corn fields are subjected to post-harvest
treatments that result in a low risk of volunteer corn growing. Those post
harvest treatments include measures such as immediate cultivation after
harvesting so that fresh plant material is broken up and exposed to decay. Risk
levels are therefore very low as any residual seed heads that might be present
will be immature and because of mulching will not have the opportunity to
It is most likely that product grown in these fields has been sold and
consumed. If the product had contained a presence of Bt11 sweetcorn, based on
the extensive testing done on other products, it is considered highly probable
that any level of presence would have been well below the 1 percent threshold
for unintended presence allowed for in the Australia/New Zealand Joint Food
Food Standards Australia New Zealand (FSANZ ), which administers the Joint
Food Standards Code assesses the safety of all GM foods before they are approved
for sale. FSANZ concluded in its safety assessment that food derived from Bt11
corn was safe for human consumption.
The New Zealand Food Safety Authority therefore considers no further action
is necessary in relation to product grown from these fields.
There were 16 fields in Gisborne, 74 fields in Marlborough and four fields in
MAF, in consultation with other government departments, is reviewing the
adequacy of the testing protocols used for imported sweet corn, maize, oilseed
rape and soya bean seeds imported for sowing. Ministers will shortly be briefed
on the conclusions reached.
No. The law does not permit unauthorised GM seeds to be knowingly imported or
planted. If GM seeds are detected, the consignment will not be allowed into New
Zealand. However, there is always a chance that low concentrations of GM seeds
may not be detected. The limit of reliable detection is about 0.1 percent (one
seed in a thousand). This is not a barrier between what is detectable and what
is not, but it indicates the level where we can confidently find GM seeds. Lower
concentrations of GM seeds may be detected, but with much less confidence.
The New Zealand testing regime is one of the strictest in the world. MAF
tests imported seed for growing in the environment at the border and if there is
any indication of unauthorised GM content it is not allowed in. MAF requires all
consignments of sweet corn, maize, oilseed rape and soya bean seeds imported for
sowing to be tested for the presence of GM material
Last year the sample sizes for testing for inadvertent GM content were
increased from 1,400 to 3,200 seeds. This means that the current testing process
will detect the presence of 1 GM seed in 1000 with 95 percent confidence.
Unless every single seed is tested (thereby destroying it), MAF cannot
guarantee 100 percent GM-free seed.
Banning imports of maize seeds would have serious negative effects in several
agricultural industries, including dairying where green-feed and maize silage
are widely used, but could still not provide a 100 percent guarantee to stop all
Imported seeds are important for many New Zealand agricultural industries –
the price and quality of seeds affects the competitiveness of these industries.
For example, maize is grown for food and is also an important stock feed in the
dairy, pig and poultry industries. Many of the best quality seeds come from
countries that grow GM crops, which are the world's major seed producers.
Banning seeds from those countries would limit access to those seeds and would
probably raise the price of seeds, which would negatively affect those
industries that rely on imported seeds.
Although the costs of a ban are not clear, the value of these crops gives an
indication of their importance. MAF estimates that the annual gross value of
maize is about $70 million and that it adds $60 million in extra production to
the dairy industry. The annual gross margin of the canola/oilseed rape crop is
about $1.8 million. New Zealand also has a seed multiplication industry worth
about $20-$30 million. This issue highlights that as a trading nation, New
Zealand faces both risks and benefits from trade. In this case, the benefits of
importing seeds outweigh the risks.
Testing at the border is rigorous and, when inadvertent GM content is found,
MAF acts immediately to control the situation. With more and more GM crops being
grown and traded around the world, there will be more opportunities for
inadvertent presence in seed supplies. On the other hand, the systems to
separate GM and non-GM crops are likely to improve, driven both by commercial
pressures and demands from governments for assurances.
It is probably inevitable that there will be some instances of GM seeds being
inadvertently imported, but with appropriate actions and ongoing assurance
systems, it should be possible to keep them isolated. There is always a chance
that some low levels of GM seeds may not be detected, but most of the time it
will be detected by the assurance systems that are in place.
MAF will investigate the suspected presence of any GM seeds as it would for
any other case where there is evidence of a breach of the Biosecurity Act 1993.
No. The two cases involve different GMOs and are kilometres apart.
For further information about The New Zealand Food Safety Authority visit:
For further information about MAF protocols visit: