Chapter 17 - Keeping Food Safe

Question 1

List three causes of food spoilage.

Answer 1

● Microorganisms
Microoraganisms such as bacteria, yeast and moulds grow on food which is rich in nutrients and moisture.
Example- Moulds on bread

●Enzymatic action
Effect of enzymes in food that speed up reactions such as browning that can lead to food spoilage.
Example: Cut apple slices

● Environmental factors
Light, oxygen, temperature, humidity, physical damage may affect result in spoilage in food.
Example: Bruised apple for physical damage

Question 2

Identify four conditions which favour food spoilage in milk.

Answer 2

● Presence of oxygen

● High temperature

● Exposure to light source

●Physical damage to the milk carton

Question 3

Differentiate the different ways to store perishable and non-perishable food.

Answer 3

● Perishable foods are high in moisture content whilst
non-perishable food have low moisture content.

● Perishable food needs to be refrigerate quickly
whilst non-perishable food can be kept at room
temperature

Question 4

Suggest four different methods of preservation to prevent food spoilage.

Answer 4

● Vacuum-packing to remove air

● Drying to remove moisture

● Food irradiation - Using ionising radiation to destroy
bacteria

● Pasteurisation or heat sterilisation using of heat to
destroy bacteria

● Freezing to reduce temperature

Question 5

Food spoilage is caused by micro-organisms such as bacteria.

(a) Name one other type of micro-organism.

Answer 5

● Mould

● Yeast

Question 6

State two conditions required for the growth of bacteria.

Answer 6

● Warmth

● Moisture

● Food

● Presence of oxygen

Question 7

Define the term cross-contamination.

Answer 7

Cross contamination occurs when micro-organisms present in raw food is transferred to cooked food,
causing food spoilage and food poisoning.