Food production and preservation

1. Food production and preservation

2. Key Words to define: Autotroph - Heterotroph - Selective breeding - Artificial selection - Fertlisers - Mycoprotein - Food spoilage - Pasteurisation - Irradiation - Sterilisation -

3. Ancient Biotechnology~50,000 years ago - at least two different species of “people” (H.sapiens, H. neanderthalensis) began to pass on cultural traditions. People could “imagine”, share ideas, plan ahead, honor their dead.They began to see the worldas something that could bemanipulated. 10,000 years ago - the traditions of agriculture and animal husbandry began to develop.Wheat, rye, barley, goats, sheep

4. Early Agriculture Even relatively primitive peoples understood that selective breeding had positive outcomes. -larger grain seeds  flour-selective breeding of goats and eventually cattle to increase milk production and meat content. Agrarian societies unknowingly participated in genetic manipulation to make useful products for humans.SELECTIVE BREEDING IS BIOTECHNOLOGY

5. Modern Example of Selective Breeding Selective Breeding of Kale (Brassica oleracea) Cabbage Brussels Sprouts Cauliflower Kohlrabi Kale

6. This is modern Kale. Its ancestor provided the stock for the selective breeding of the other subspecies.

7. The large terminal buds of the plant were selected to produce cabbage.

8. Large lateral buds were selected to produce Brussels Sprouts

9. Principles of artificial selection: • Breeders choose features they wish to improve. • Individuals with those features are bred together. • Offspring with improvement are selected to breed in next generation. • Continues over next 10+ years

10. Cauliflower was produced by selecting for large, white flower stalks.

11. For broccoli, large stems and flower stalks were both selected.

12. Kohlrabi was produced by selecting for short, fat stems

13. And this is modern Kale. Remember, allof the vegetables that you have seen are the SAME SPECIES - EACHPRODUCED BYSELECTIVE BREEDING; TAKING ADVANTAGE OF WILD TYPE GENES AND NATURAL MUTATIONS.

14. Coming to a supermarket near you soon…

15. Other examples - crops: • Yields of grain (wheat, rice), roots (carrots) and tubers (potatoes) • Pest resistance – insects, fungi, bacteria, viruses • Better quality – appearance, taste

17. Other examples - livestock: • Yield of meat, milk, eggs • Fast growing breeds • Disease resistance ( eg blue tongue disease) • Quality – lean, low fat meat

18. All the same species – Ovisaries

19. Improving the environment improves food production…

20. Fertlisers – NPK and Mg: • Nitrates – making amino acids • Phosphates – DNA, RNA, ATP, phospholipids • Potassium – enzyme co-factor; guard cell opening • Magnesium – making chlorophyll

22. Organic vs inorganic?

23. Inorganic: • Higher yield, cheaper, trace contaminants • Organic; • Lower yields, more expensive, no trace contaminants

24. Pesticides • Herbicides – kill weeds that compete • Fungicides – against mildew, blight and rust • Insecticides – applied when levels threaten economic loss. • Organic – use none of the above. • Crop rotation and natural predators (biological control)

25. Organic farming

26. Use of Microorganisms Bacteria cheese, yogurt, antibioticsFungi cheesesYeast ( single celled fungus) bread, beer C6H12O6 CO2 + C2H5OH Louis Pasteur (1860’s)clearly demonstrated that microbes are responsible for fermentation.

27. Produce traditional products in clever, new ways • increase crop productivity, meat production, and milk production “The miracle of Genetic Engineering”

28. Mycoprotein Uses a fungus Fusarium ( strain PTA-2684) First discovered in a field in Buckingham in 1967 Now grown on an industrial scale to make ‘Quorn’

29. Advantages • Microbes grow quickly – high yields in short time. • Uses less land to grow; can be set up anywhere • Uses waste material ( eg whey) as a substrate • No ethical issues with breeding / vegans • Low fat or no-fat foods

30. Disadvantages • Contamination of culture vessels • Consumer resistance / suspicion • Need to have a substrate, produced by something else. • Needs purifying before use

32. The future - modifying genetics to produceorganisms with new “recombinant” traits. -plants with resistance to disease and parasites. -replacing a defective gene in a crop plant or animal ‘Agrobacterium’

33. Food Spoilage Aspergillus fungus – the aflatoxins it produces are carcinogenic

34. Preservation – removes one of the conditions that microbe needs to survive…

35. Salting / Sugaring • Lowers wp. Removes water from microbes by osmosis • Eg salted cod, jams

36. Pickling • Ethanoic acid (vinegar) – lowers pH to <4 • Microbe enzymes denature. • Eg pickled cabbage, onions

37. Heat Treatment -1 • Pasteurisation – brief flash heating to 72C for 15 seconds. • Kills pathogens but not Lactobacillus, so flavour is preserved.

38. Heat Treatment -2 • UHT – brief flash heating to 135C for 15 seconds. • Kills all bacteria, but flavour is compromised.

39. Freezing • Water is frozen, so not available to microbes. • Enzymes are inactivated. • Eg meat

40. Irradiation • X-rays or Gamma rays kill microbes by denaturing proteins and DNA. • Eg fruit, prawns

43. Homework: • 1. Describe, using examples from agriculture, the principles of selective breeding. • 2. Explain the term ‘food spoilage’ and describe how food may be prevented from going ‘off’.