Science Form 5/Chapter 1

Food poisoning Food poisoning is an illness caused by eating food that has been contaminated by microorganisms. 2. They infect body tissue in the intestine or produce poison (toxins) cause the symptoms of the illness like nausea, vomiting, abdominal pain and diarrhoea. 3. Food may become contaminated by microoganisms by dirty hands. 4. Vegetables are manured using animal waste cause food poisoning. 5. Food poisoning can prevented by : a.Avoid eating raw or undercooked meat, fish and shellfish. b.Avoid eating shellfish from contaminated waters. c.Wash vegetables thoroughly to traces of animal manure. d.Cover food to prevent contaminated. e.Wash hands before handling food.

Science Form 5/Chapter 1

HARMFUL EFFECTS OF MICROORGANISMS

1. Microorganisms cause diseases called pathogen.

Example: tooth decay, food poisoning and diseases

are all caused by microorganisms.

Tooth decay (Caries)

1.Tooth decay caused by bacteria.

2.After eating, layer of plaque is formed on the suface of teeth.

Plaque = saliva + food residue + bacteria

3. Bacteria act on the food residue, produce lactic acid.

4. Lactic acid corrodes the enamel and the dentin.

When damage reaches the pulp (nerves and blood vessels)

toothache is felt.

5. Caries can be prevented by:

a. Brushing and flossing after meals

b. Avoiding sweet food

c. Adding fluoride to tap water

d. Regular dental check-ups