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Environmental Education Lecture Notes: 2.4 Genetically Modified Food.

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Presentation on theme: "Environmental Education Lecture Notes: 2.4 Genetically Modified Food."— Presentation transcript:

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) Cell possessing a nucleus Gene DNA possession of ear lobe

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 SAVR TM tomato, was marketed in the United States in –Slower ripen rate –Ripen longer on vine –Fully developed flavors Flavr Savr Tomato developed by Calgene (Sources:

8 Flavr Savr TomatoTraditional 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. Ripe and Increas ed Flavour. Ripe but decrea sed flavou r. Supermarket The traditional tomato is sprayed with ethylene after shipping to induce ripening. 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 Fish Tomato-fish Replicated DNA Denucleated fish egg Fish cell Fish DNA Tomato cell Tomato DNA Desired gene 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] Approaches –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.MG.M Harmful?

16 Labeling of GM Food [2] Labeling for Substantially DifferentLabeling of all GM foods ProsAlert 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 ConsMay not satisfy needs of all consumers Additional costs Difficult to enforce due to detection limits Countries adopting Canada, USAEuropean Union, Australia, New Zealand Pros and Cons of labeling systems

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 )


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