GMOs: a food safety perspective'

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GMOs a food safety perspective.
C.D. (Kees) de Gooijer Harry Kuiper RIKILT-Insti
tute for Food Safety, Wageningen University and
Research Center (WUR), The Netherlands
ASEM workshop on agrofood bioethics, Kuala
Lumpur, 22-24- June, 2002
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Debate on Genetically Modified Food Crops
Species barriers are crossed and unknown
effects Impact on the environment Can we test
the safety of (GM-)foods adequately Long term
effects on human health GM-free foods, labelling
and traceability, Contribution to a sustainable
agriculture Whose interest
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First Generation of Modified Food Plants with
Agronomical Traits
Improved disease resistance (viruses,
fungi) Improved pest resistance (lepidoptera,
beetles) Tolerance for herbicide (glyphosate,
glufosinate) Slow ripening
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Relatively small modifications
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Second Generation of GMO Food Plants with
Improved Quality Traits
Improved quality of seed storage proteins Higher
starch content, waxy starch and novel
carbohydrates Better oil quality (low saturated
fatty acids) Fortification with micro nutrients
and antioxidants Reduction/elimination of
allergens and natural toxins Increased absorption
of critical nutrients Carrier for edible vaccins
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More complex modifications
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Future Transgenic Crops

• Golden rice provitamin A
• Iron-fortified rice transgenic for ferritin
• Tomato ?-carotene / lycopene enriched
• Lupin higher methionine levels
• Maize detoxification of mycotoxins
• Insect resistant maize transgenic for avidin
• Cassava detoxification of cyanogens
• Fructan-beet non caloric sweetener
• Alfalfa transgenic phytase, P-availability
• Canola vitamin E enriched
• Coffee-beans caffeine-free

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New Healthy Diets and Major Uncertainties
Which compounds/fruits/vegetables Bioavailability
of compounds Interaction between
components Matrix effects on availability of
nutrients Current (non)-nutrient levels and
variability Losses of compounds through food
processing Scientific evidence of risk/benefits
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Report
New Developments in Crop Plant Biotechnology and
their Possible Implications for Food Product
Safety
G.A. Kleter, M.Y. Noordam, E.J. Kok en H.A.
Kuiper Internet edition http//www.rikilt.wagenin
gen-ur.nl/News/biotechnology.html request paper
copy g.a.kleter_at_rikilt.wag-ur.nl
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Safety Evaluation of Foods

• Starting point
• Foods are complex mixtures of macro- and
  micro-nutrients, fibers, anti-nutrients, natural
  toxins and health-promoting substances.
• Safety evaluation of whole foods as performed
  with single food additives is not possible.

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Concept of Substantial EquivalenceOECD, 1993

• Existing traditional foods are considered to be
  safe, through their long history of use
• Traditional foods can serve as a basis for the
  safety assessment of GM foods, since most of
  these foods are obtained from them (concept of
  Substantial Equivalence)

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Concept of Substantial EquivalenceOECD, 1993
Identification of differences which should be
further assessed regarding their impact on the
safety and nutritional status of the genetically
modified food. Thus a Systematic Comparison of
Agronomic properties, Morphological
characteristics, Compositional parameters of the
GM organism and its closest traditional
counterpart.
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Practical Implications of the S.E. Determination
(i) Choice of the appropriate comparator (ii) Sele
ction of key nutrients, anti-nutrients and
toxins (iii) Natural variations in
agronomical/compositional properties (iv) Trial
sites, replicates and years (iv) Availability
analytical methods
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Different Scenarios for S.E. Establishment

• S.E. can be established between the GM food and
  its traditional counterpart no further testing
  needed
• S.E. can be established except for the inserted
  new trait(s) additional testing needed
• S.E. cannot be established further toxicological
  testing needed

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Concept of Substantial Equivalence
Is not a safety assessment in itself It
identifies but does not characterise the
hazard Is the starting point of the assessment,
rather than the endpoint Structures the safety
assessment of a GM food relative to its
conventional counterpart
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A Brazil-nut Allergen in Transgenic Soybeans

• 2S methionine-rich albumin transferred from
  Brazil nut to soybeans
• 2S albumin is a major Brazil nut allergen
• Patients allergic to Brazil nuts showed positive
  reactions to extracts of transgenic soybeans
• Transgenic soybeans never reached the market
• Nordlee et al., The New England Journal of
  Medicine, March 1996 688-692

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Unintended Effects in Conventional Breeding

• General phenomenon
• Selection according to phenotypic/agronomic
  parameters
• Backcrossing
• Screening for selected compounds (e.g. starch,
  glycoalkaloids in potatoes)

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Unintended Effects in Conventional Breeding
Potato

• Pest resistance S. tuberosum x S. chacoense
  glycoalkaloids up
• A number of confirmed cases of human poisoning

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Unintended Effects in Genetic Engineering
Breeding 1
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Safety Assessment of GM Food
Unintended effects
Profiling techniques ? non-targeted approach
Specific analysis ? targeted approach
www.entransfood.com
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Platform of OMICS Technologies
AGRONOMICS
PHENOTYPICS
GENOMICS
PROTEOMICS
METABOLOMICS
STATISTICS
Metabolite expression
Gene expression
Protein expression
Data integration
Unintended effects?
Function
DIFFERENCES
COMPONENTS
PROTEINS
DNA/mRNAs
TISSUE
PLANT
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Integrated Non-Targeted Approach
Non-GM
GM
Large scale screening of simultaneous expression
of genes/proteins/metabolites
Detection of altered profiles/differences
Comparison with natural variabilities
Significant unintended difference or not
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Conclusions Profiling Techniques

• Problems with profiling techniques still to be
  solved
• Standardisation of sample collection, preparation
  and extraction
• Standardisation and validation of measurements
• Limited availability of data on profiles and
  natural variations
• Handling of large data sets on bioinformatics

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Conclusions
1. The principle of Substantial Equivalence is a
robust strategy to identify hazards of GM foods,
which should be further investigated 2. GM foods
with no conventional comparitor may need
extensive safety testing safety margins,
nutritional imbalances, bioavailability, matrix
and interaction effects.
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Conclusions
3. Profiling methods are promising and should be
further developed to identify and assess
unexpected alterations in the composition of GM
foods 4. Information on health-benefit aspects of
GM foods is still scarce 5. Greater transparency
and interactive dialogue with the consumer is
needed about the risks and benefits of the GM
technology
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Acknowledgements

• Harry Kuiper
• Gijs Kleter
• Hub Noteborn
• Esther Kok
• Irene König-Lamers
• Nicole van Hal
• Jaap Keijer