1. Recap food production Why are plants so important in the production of food? List the 3 stages of selective breeding Which types of chemicals are used to improve food production Choose one type and explain how its use would increase yield.

2. Objectives Describe the spoilage of food due to microorganism contamination Identify treatments used to prevent food spoilage Evaluate the these treatments

3. Microorganisms and food

4. http://www.youtube.com/watch?v=S12zZhdO ckc http://www.youtube.com/watch?v=S12zZhdO ckc http://www.youtube.com/watch?v=yFIqj0DM Fow&feature=related http://www.youtube.com/watch?v=yFIqj0DM Fow&feature=related

5. Visible growth Most obvious with fungi E.g. black Mucor and blue/green Penicillium moulds

6. External digestion Release of enzymes to break down food so it can be absorbed by the microorganism Often smells sweet Eventually reduced to mush

7. Toxin production Some microorganisms produce toxins E.g. Clostridium botulinium produces toxin so toxic that 1µm will kill a human

8. Infection Microorganisms in food can cause infection (food poisoning) E.g. Salmonella http://www.youtube.com/watch?v=gEwzDydciWc

9. Conditions required for growth Organic food - proteins, fats, carbohydrates Suitable temperature Water Oxygen (in some cases) Suitable pH

10. Food treatment Cooking Pasteurising Drying, salting, sugar coating Smoking Pickling Irradiation Cooling/freezing

11. http://www.food.gov.uk/safereating/rad_in_f ood/irradfoodqa/ http://www.food.gov.uk/safereating/rad_in_f ood/irradfoodqa/

12. Prevent further contamination Canning Vacuum packing Packaging

13. Objectives Describe the spoilage of food due to microorganism contamination Identify treatments used to prevent food spoilage Evaluate the these treatments