The following options can cause contamination:
- Staff coughing and sneezing over food
- Staff with poor personal hygiene
- Staff not wearing appropriate PPE when preparing food
- Preparing raw and cooked meats on the same chopping board
These practices can introduce harmful bacteria or pathogens that can lead to foodborne illnesses. The other options listed (overcooking food, leaving cooked rice in the fridge) are less directly related to contamination but can still affect food safety in different ways.