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 Health Science Paper 2, May/June 2009
 Questions: 1 2 3 4 5 Main
Strength
Weakness/Remedies

Question 1

(a)     (i)    Give two reasons why food is cooked.                                     [2 marks]

(ii)    State three cooking methods.                                                   [3 marks]

(b) Mention one advantage and one disadvantage of each method stated in (a)(ii) above.                                                                     [6 marks]

(c) Describe how each of the following methods helps to preserve food:

(i)         freezing;
(ii)        dehydration;
(ii)        salting.                                                                                  [9 marks]

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observation

This question was attempted by many candidates and their performance was fair.

In part (a)(ii) some candidates who could not state cooking methods wrote gas cooker, firewood, electric cooker.  Candidates who knew the methods could not mention one advantage and one disadvantage of each method.  In part (c) few candidates could describe how each of freezing, dehydration and salting helps to preserve food

Cooking Methods
(a)(ii)  -           Boiling;

• Roasting/baking/smoking;
• Steaming;
• Frying;
• Stewing.

• fast method;
• retains natural taste of food;
• makes food tender/soft;
• kills germs.

• Not suitable for all kinds of food e.g. grains, powdery foods;
• Loss of water, soluble vitamins.

• It reduces the loss of nutrients;
• Food flavour retained;
• Reduces fat content of food;
• Kills germs/sterilizes food.

• Moisture is lost by evaporation;
• Food shrinks in size;
• High temperature may toughen protein digestion.

c.         How the following methods help to preserve food:

Freezing
This is the process of cooling food/reducing the temperature to between 50C to 0OC. At this low temperature bacteria activity is slowed down/completely stopped thereby preventing spoilage of food.

Dehydration
This involves drying the food by different means, e.g. sun, fire, oven etc. The absence of water eliminates an environment in which bacteria can thrive/stops the activities of bacteria thereby preventing spoilage of food.

Salting
This involves the adding of salt to food, making the solution of food very strong; if bacteria is present in food water is drawn out of the bacteria by osmosis; thereby killing the bacteria/preventing spoilage of food and preserving the food.