Question

9. A piece of raw meat was left in an uncovered bowl for seven days. (i) State four likely changes that would be observed in the meat. (ii) Name the biological process that led to the changes observed in the meat. (iii) On the table below, list four methods of preserving meat to prevent it from the changes stated, and mention the principle involved in the methods.

Accepted Answer

(i) Likely changes: bad odour/offensive smell; change in texture/slimy texture; change in colour/greenish colour/rot; presence of water around the meat; presence of microbial growth; presence of maggots (any four).
(ii) Biological process: Decay/decomposition/putrefaction.
(iii) Methods and principles:
Freezing — reduces the growth of micro-organisms.
Drying — removal of moisture/water content to prevent growth/multiplication of microbes.
Salting — salt kills micro-organisms by increasing the osmotic pressure in the meat.
Frying — involves the immersion of foods in boiling oils/dehydrates the items and decreases microbial growth.
Canning — involves heating to kill micro-organisms.
Smoking — reduces the water content of the meat; kills micro-organisms; prevents the entry of new ones. (Any four)

WAEC Biology 2024 Theory — Question 9

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