6Why GM Food?  Increase crop yields Increase the tolerance of crops to adverse growing conditions, e.g. droughtImprove the nutrient composition of crops, e.g. increase the protein content of riceProvide resistance to crop pests and reduce the use of pesticidesImprove sensory attributes of food, e.g. flavor, textureImprove processing characteristics so as to reduce wastage and costsEliminate allergenicity of some food
7Why GM Food?  - ExampleThe first GM whole food, FLAVR SAVRTM tomato, was marketed in the United States in 1994.Slower ripen rateRipen longer on vineFully developed flavorsFlavr Savr Tomato developed by Calgene(Sources:
8Flavr 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 harvestingThe 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.SupermarketFlavr Savr is modified tomato for suiting modern productions and distributions. Credit: Owen Koo
9How to Produce GM Food?  ConceptConvert existing gene(character) of or add new gene (character) to target speciesPracticeExtract an desirable gene from source species and introduce to target species
10How to Produce GM Food?  - Example Tomato DNATomato cellFish DNAFish cellDesired geneReplicated DNAFishTomatoDenucleated fish eggTomato-fishCredit: Owen Koo
11Is GM Food Safe or Harmful?  MonitoringBefore released to markets, tests and approval by specific organization are requiredIn USA, GM food is regulated by three federal agencies:The Food and Drug AdministrationThe Environmental Protection AgencyThe United States Department of Agriculture
12Is GM Food Safe or Harmful? Safety AssessmentsPrinciple of “Substantial Equivalence” is endorsed byWorld Health Organization (WHO)Food and Agriculture Organization (FAO)Organization for Economic Cooperation and Development (OECD)
13Is GM Food Safe or Harmful? 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 counterpartKey considerationsCharacteristics of donor and host organismsCompositionDietary IntakeNutritional dataToxicological dataAllergenic properties
14Is GM Food Safe or Harmful? Potential ProblemsGreen groups and consumer groups fear that GM foods may bring about disastrous consequences such as :Unintended modification due to cross pollinationUpset the equilibrium of ecosystemsDevelop super pestsWhether gene transfer among animals and plants is acceptableWorry about eating a food containing a gene from something the eater should avoid due to religious, health or other reasons??
15Labeling of GM Food  Harmful? Approaches G.M Labeling for Substantially DifferentMandatory 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 labeledLabeling of all GM foodsConsumers’ “right of knowledge” should be protected, so all products containing GM materials must be labeledG.MHarmful?
16Labeling of GM Food  Pros and Cons of labeling systems Labeling for Substantially DifferentLabeling of all GM foodsProsAlert consumers on allergenicity, composition or nutrientsNo significant additional costsLittle international trade implicationsInform consumers which is GM foodEnhance surveillance and tracing on GM foodConsMay not satisfy needs of all consumersAdditional costsDifficult to enforce due to detection limitsCountries adoptingCanada, USAEuropean Union, Australia, New Zealand
17Situation in Hong Kong Availability of GM Crops in Hong Kong Existing Food Control in Hong KongFuture Plan
18DiscussionCompare 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?
19Relevant WebsitesGenetically Engineered Foods: Fears and FactsScientific American: Poison Plants? (includes cases for and against, and related links)Transgenic Crops: An Introduction and Resource GuideImpacts of Adopting Genetically Engineered Crops in the U.S.List of Genetically Altered Food - from the International Center for Technology AssessmentGenetically Modified Food – Hong Kong Government專題探討 - 基因改造食物的測試方法)