Food Chemistry Chapter 17 in Green / Damjii Chapter X in Nuess Chapter X in Oxford Study (no resource in Chang)

Homework Read F5– GM Foods- pp. 486 Do Qs on p 493 F.5: Genetically Modified Food

Genetically modified food is a food that is produced by modifying the DNA sequence of micro-organisms, plants and animals. Genetic engineering in plant foods may involve… – Put a gene in to change behavior of cell – Inactivate a gene to remove undesired behavior – Modify a gene to get higher yields of products F.5.1: Define a genetically modified (GM) food.

Genetic engineering may be used – Directly – develop a transgenic plant / animal Plants resistant to herbicides, contain more vitamins, can grow in poor soils or harsh conditions – Indirectly – produce enzymes for food processing using genetically modified micro-organisms GM bacteria make enzyme (protease chymosin) to help convert milk into cheese – reducing the need for rennet from the stomachs of calves. Ascorbic acid, aspartame, caffeine-free coffee F.5.1: Define a genetically modified (GM) food.

ADVANTAGES (1)Pest, herbicide, and disease resistance  Reduce need to use herbicides, pesticide, vaccines… all of which add to production costs, may impact our environment, and may leave their own toxic residues in food. – Ex: Crop is made to be more resistant to a particular herbicide so that less of the herbicide needs to be used to get rid of weeds – Ex: Bananas have gene that resists attack by nematods – Ex: Potatoes have gene added to resist fungal disease F.5.2: Discuss the benefits and concerns of using GM foods.

ADVANTAGES (2)Improved qualities and range  Enable a food to be grown in a wider range of climatic conditions (drought, high salt content in soil &/or groundwater)... produce greater yields… mature in a shorter time. – Ex: tobacco and potato plants get a gene that makes them more cold tolerant – Ex; higher yielding rice varieties &/or rice that contains additional vitamins and minerals to prevent nutrient deficiencies – Ex: maize that can grow in areas with lower rainfall – Ex: FlavrSavr tomato – PG gene is inhibited allowing tomato to stay firm longer… to allow for harvesting, storage, and distribution… tomato is still able to ripen… just not loose its firmness. F.5.2: Discuss the benefits and concerns of using GM foods.

DISADVANTAGES (1)Possible impact on health  Subtle differences in composition may cause allergic reactions in people  Unknown impact on our digestive system ??? (2)Possible damage to natural ecosystems  Currently gm plants are limited to particular farms… but there is a risk that pollen from them will escape into the wild population with unforeseen consequences. F.5.2: Discuss the benefits and concerns of using GM foods.