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WALT Know reasons for food spoilage. Know benefits of preserving food. Know some methods of preserving food.

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Presentation on theme: "WALT Know reasons for food spoilage. Know benefits of preserving food. Know some methods of preserving food."— Presentation transcript:

1 WALT Know reasons for food spoilage. Know benefits of preserving food. Know some methods of preserving food.

2 What causes spoilage of food?

3 Three main groups of microbes that cause spoilage : Bacteria Moulds Yeasts Source :http://resources.schoolscience.co.uk/SGM/sgmspoil1.html

4 Bacteria – on raw meat, raw fish, raw milk, Yeasts and acid/salt tolerant bacteria -on cured meat Yeasts and moulds -On butter, yoghurt, cheese, fruits, vegetables Moulds - On cereals, nuts,

5 Preservation of food ? Any ideas???

6 Which methods do you know?

7 Preservation of food Heating – pasteurisation, sterilising Cooling – refrigeration, freezing Chemicals – curing, pickling, fermentation, Sulphur dioxide, benzoic acid, ascorbic acid, propionic acid Drying Freeze drying Packaging Irradiation

8 Questions 1.Why does food go bad? 2.Which methods do you know? 3.Why do we use preservation methods?

9 Ham contains more vitamin C than a piece of fruit Vitamin C is also named ascorbic acid 137 milligrams 4 grams

10 Food preservation experiment Food gets mouldy after a while. That shows us that …

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12 Mould, a problem for humans

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