(a)A piece of raw meat was left in an uncovered bowl for seven days. Use the information to answer questions 3(a) and 3(b).
(i) State four likely changes that would be observed in the meat.
(ii) Name the biological process that led to the changes that are observed in the meat.
(iii)On the table below, list four methods of preserving meat to prevent it from the changes stated in 3a(i) and mention the principle involved in the methods.
| Four methods of preserving the meat | One principle involved in the preservation method |
(iv)Name two environmental factors that may be responsible for the changes in 3a(i)
(b) Name one method of preserving the following food items:
(i) dried maize grains; (ii) fresh tomatoes; (iii) vegetables; (iv) beans; (v) milk
Explanation
a(i)four likely changes that would be observed in the meat.
- bad or offensive odour
- presence of maggot
- microbial growth
- colour change
- change in texture
(ii)The biological process that led to the changes that are observed in the meat is decay or putrefaction.
(iii)
|
Four methods of preserving the meat |
One principle involved in the preservation method |
| Salting | Salt inhibits microbial growth or kills microorganisms by increasing the osmotic pressure in the meat |
| Frying | Involves the immersion of the meat in the boiling oil. It dehydrates the food and reduces microbial growth |
| Freezing | Reduces microbial growth by storing food at very low temperature. |
| Drying | Removal of moisture content in order to inhibit microbial growth. |
| Canning | Involves heating to destroy microorganisms |
(iv)Environmental factors that may be responsible for decay
- Moisture content
- Temperature
- Humidity
- Oxygen
(b) Method of preserving
(i)Dried maize grain: Store in jute bag; sun drying; storage chemical treatment; pack in silos barn
(ii)Fresh tomatoes: Canning; drying; freezing
(iii)Vegetables: refrigeration; drying; curing
(iv)Beans: Low humid container; chemical treatment; sun drying
(v)Milk: Pasteurizatio;canning