Improving food production

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  • Created by: Buffya
  • Created on: 31-05-13 19:34
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  • Improving food production
    • Microorganisms
      • Harmful
        • Can spoil food by releasing enzymes to digest it, producing toxins and attacking stomach lining
        • Ways to prevent growth
          • Irradiation is using ionising radiation to disrupt DNA structure
          • Pasteurising - eat to 72C for 15 seconds then cool to 4C
          • Salting dehydrates the microgrganism
          • Pickling adds acid which denatures enzymes
          • Cooling and freezing slows down enzyme activity
      • Useful
        • Lactobacillus bacteria is used in production of cheese and yoghurt
        • Anaerobic respiration is used in bread and in alcohol
        • Single cell proteins can be used in the production of food
          • Fusariam venenatum is Quorn and a meat substitute
          • Grown on any organic substrate
          • Advantages are that they contain no animal fat or cholesterol, have a very fast growth rate, have no animal welfare issues and remove waste products
          • Disadvantages are that it doesn't have some taste or texture, are grown in an environment where pathogens can also grow and has to be isolated
    • Selective breeding
      • First isolate the pair of organisms with the desired characteristics
        • Artificial selection through the offspring to find those with the best combination
          • Inbreeding over generations (controlled)
      • We apply selection pressure (not natural selection)
        • High milk yield
        • Fast growth rates e.g. salmon
        • High egg yield
      • Marker-assisted selection is when part of the DNA is used to recognise desired characteristics
        • Wild tomatoes with resistance to yellow leaf curl virus
        • Apples have been bred in this way
    • With chemicals
      • Fertilisers replace nutrients that previous crops may have removed form the soil
      • Pesticides kill organisms that cause disease within crops
      • Antibiotics are chemicals that kill or prevent reproduction in bacteria. This reduces spread of disease

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