NATIONAL SEMIFINAL STAGE 2025
Keta SHTS: 38
Koforidua SHTS: 27
Tamale SHS: 24
QUESTION
A student fell ill within hours of eating fried rice and chicken that had been left in a chow box for too long, allowing disease-causing organisms to grow. Name three possible non-fungal pathogen genera or groups that could have caused the illness.
ANSWER: Any three of: Staphylococcus, Salmonella, Campylobacter, Bacillus, Clostridium, Shigella, Escherichia (E. coli), Vibrio, or Norovirus.
EXPLANATION
These are the classic bacterial (and, for Norovirus, viral) causes of foodborne illness from improperly stored cooked food — "non-fungal" simply excludes mold/yeast-based food spoilage, leaving bacteria and viruses as the answer pool.
PRACTICE QUESTIONS
1. Which bacterium is commonly associated with food poisoning from reheated rice?
ANSWER: Bacillus cereus.
2. Which bacterium produces toxins in food that has been handled and left warm?
ANSWER: Staphylococcus aureus.
3. Which bacterium is commonly found in raw poultry and eggs?
ANSWER: Salmonella.
4. Why does cooked food left out at room temperature become unsafe?
ANSWER: Bacteria multiply quickly in warm conditions.
5. Name a virus that causes food-borne illness.
ANSWER: Norovirus.
6. State two symptoms of food poisoning.
ANSWER: Vomiting and diarrhoea.
7. State two ways of preventing food poisoning.
ANSWER: Cooking food thoroughly and keeping it refrigerated.
8. Which bacterium causes traveller's diarrhoea and can be found in contaminated water?
ANSWER: Escherichia coli.
9. What is cross-contamination?
ANSWER: The transfer of microbes from raw food to cooked food, or from surfaces to food.
10. Why is it unsafe to leave cooked rice at room temperature for a long time?
ANSWER: Endospores that survive cooking germinate and produce toxins.
11. Which bacterium causes botulism in badly canned food?
ANSWER: Clostridium botulinum.
12. Which bacterium causes bacillary dysentery?
ANSWER: Shigella.