1. Environmental Education
Lecture Notes: 2.4
Genetically Modified Food

2. Content Introduction What are genes? Why GM food?
How to produce GM food?
Is GM food harmful?
Labelling of GM food
Situation in Hong Kong

3. Introduction
Genetic engineering modifies genetic materials of organisms or viruses
Applying such techniques to crops or other food source organisms can improve food production

4. What are Genes?
A gene is DNA segments contributing to a phenotype or function
(Information of a character or function)
Gene
possession of ear lobe
Cell possessing a nucleus
DNA

5. GM corn is
a common staple
(Source:

6. Why GM Food? [1] Increase crop yields
Increase the tolerance of crops to adverse growing conditions, e.g. drought
Improve the nutrient composition of crops, e.g. increase the protein content of rice
Provide resistance to crop pests and reduce the use of pesticides
Improve sensory attributes of food, e.g. flavor, texture
Improve processing characteristics so as to reduce wastage and costs
Eliminate allergenicity of some food

7. Why GM Food? [2] - Example
The first GM whole food, FLAVR SAVRTM tomato, was marketed in the United States in 1994.
Slower ripen rate
Ripen longer on vine
Fully developed flavors
Flavr Savr Tomato developed by Calgene
(Sources:

8. Flavr Savr Tomato Traditional Tomato
The Flavr Savr tomato ripens on the vine – resulting in fuller flavour. It is modified so that it remains firm after harvesting
The traditional tomato must be harvested while it is still green and firm so that it is not crushed on the way to the supermarket.
The traditional tomato is sprayed with ethylene after shipping to induce ripening.
Ripe and Increased Flavour.
Ripe but decreased flavour.
Supermarket
Flavr Savr is modified tomato for suiting modern productions and distributions. Credit: Owen Koo

9. How to Produce GM Food? [1]
Concept
Convert existing gene(character) of or add new gene (character) to target species
Practice
Extract an desirable gene from source species and introduce to target species

10. How to Produce GM Food? [2] - Example
Tomato DNA
Tomato cell
Fish DNA
Fish cell
Desired gene
Replicated DNA
Fish
Tomato
Denucleated fish egg
Tomato-fish
Credit: Owen Koo

11. Is GM Food Safe or Harmful? [1]
Monitoring
Before released to markets, tests and approval by specific organization are required
In USA, GM food is regulated by three federal agencies:
The Food and Drug Administration
The Environmental Protection Agency
The United States Department of Agriculture

12. Is GM Food Safe or Harmful?[2]
Safety Assessments
Principle of “Substantial Equivalence” is endorsed by
World Health Organization (WHO)
Food and Agriculture Organization (FAO)
Organization for Economic Cooperation and Development (OECD)

13. Is GM Food Safe or Harmful?[3]
The concept of “Substantial Equivalence”
If a new food or component is found to be substantially equivalent to an existing food or component, the or component is considered to be as safe as its conventional counterpart
Key considerations
Characteristics of donor and host organisms
Composition
Dietary Intake
Nutritional data
Toxicological data
Allergenic properties

14. Is GM Food Safe or Harmful?[4]
Potential Problems
Green groups and consumer groups fear that GM foods may bring about disastrous consequences such as :
Unintended modification due to cross pollination
Upset the equilibrium of ecosystems
Develop super pests
Whether gene transfer among animals and plants is acceptable
Worry about eating a food containing a gene from something the eater should avoid due to religious, health or other reasons ? ?

15. Labeling of GM Food [1] Harmful? Approaches G.M
Labeling for Substantially Different
Mandatory labeling produces a negative image on GM food, and since GM food available in market are safe, only those that are not substantially equivalent should be labeled
Labeling of all GM foods
Consumers’ “right of knowledge” should be protected, so all products containing GM materials must be labeled
G.M
Harmful?

16. Labeling of GM Food [2] Pros and Cons of labeling systems
Labeling for Substantially Different
Labeling of all GM foods
Pros
Alert consumers on allergenicity, composition or nutrients
No significant additional costs
Little international trade implications
Inform consumers which is GM food
Enhance surveillance and tracing on GM food
Cons
May not satisfy needs of all consumers
Additional costs
Difficult to enforce due to detection limits
Countries adopting
Canada, USA
European Union, Australia, New Zealand

17. Situation in Hong Kong Availability of GM Crops in Hong Kong
Existing Food Control in Hong Kong
Future Plan

18. Discussion
Compare and contrast traditional breeding and genetic modifications.
What are the benefits of GM food for us?
Will you buy GM food from the market? Why?

19. Relevant Websites
Genetically Engineered Foods: Fears and Facts
Scientific American: Poison Plants? (includes cases for and against, and related links)
Transgenic Crops: An Introduction and Resource Guide
Impacts of Adopting Genetically Engineered Crops in the U.S.
List of Genetically Altered Food - from the International Center for Technology Assessment
Genetically Modified Food – Hong Kong Government
專題探討 - 基因改造食物的測試方法)