Theory question 105
Microorganisms and HealthState the principles involved in the following methods of food preservation: (a) (i) Salting (ii) Refrigeration (iii) Drying (iv) Smoking (v) Chemicals
(b) State four problems that may be caused by human overpopulation
(c) Explain three ways by which the government may increase food production
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(a)(i) Salting draws water out of the food and microorganisms by osmosis, so they cannot grow.
(ii) Refrigeration: low temperature slows down or stops the growth of microorganisms and enzyme action.
(iii) Drying removes water that microorganisms need to grow.
(iv) Smoking dries the food and coats it with chemicals from the smoke that kill or keep off microorganisms.
(v) Chemicals (preservatives such as sodium benzoate, vinegar, sugar) kill microorganisms or stop their growth.
(b) Any four: shortage of food/famine; overcrowding and poor housing (slums); spread of diseases; unemployment; pollution and poor sanitation; pressure on social amenities (schools, hospitals, water); crime; deforestation and loss of farmland.
(c) Any three, explained: give farmers loans/credit and subsidised fertilisers and tools; mechanise farming; provide improved seeds and livestock through research; provide irrigation; good storage, processing and roads to reduce waste; agricultural extension services to teach farmers; land reform to make land available.
For each preservation method, say how it stops microorganisms.