Cleaning, Disinfection and Pest Control
This domain tests the difference between cleaning and disinfecting, the correct sequence for a cleaning schedule, the factors that make disinfection work, and how to recognise and act on pest activity. Questions often give a surface or an item and ask which process it needs.
Cleaning versus disinfection
Cleaning removes visible dirt, grease and food debris - it physically removes many organisms but does not reliably kill those left behind. Disinfection reduces organisms to a safe level using heat or chemicals, but only works on a surface that is already clean. Sterilisation is not required in food premises.
The six-stage method
- Pre-clean - remove debris and loose dirt.
- Main clean - hot water and detergent.
- Rinse.
- Disinfect - food-safe sanitiser at the correct concentration and contact time, or heat.
- Final rinse - if the sanitiser requires it.
- Dry - air dry where possible; never dry with a dirty cloth.
Factors that determine disinfection success
- Concentration - dilute exactly as instructed; too weak fails, too strong can be toxic or taint food.
- Contact time - usually 30 seconds to 5 minutes depending on the product.
- Temperature - many sanitisers work best in warm water, but very hot water can degrade the chemical.
- Cleanliness of the surface - soil inactivates sanitiser.
Dishwashers should wash at around 60 °C and rinse at 82 °C. Two-stage cleaning uses detergent then sanitiser. Cleaning schedules must state what, how often, with what, by whom, and how it is checked.
Pest control
Signs include droppings, gnaw marks, smear marks, live or dead insects, cocoons, feathers, nests, gnawed packaging and unusual smells. Control has four parts: proofing the building (mesh, door brushes, sealed gaps), good hygiene (no food or water available), monitoring (checking bait stations and reporting), and professional treatment by a competent contractor. Never use pest bait near food, and never handle pests without protection.
Worked example
An examiner describes a chopping board used for raw chicken that is scrubbed with detergent, rinsed and put away wet. Reasoning: it has been cleaned but not disinfected, and air drying was not used. The correct approach is detergent wash, rinse, food-safe sanitiser at the label concentration and contact time, final rinse if required, then air dry on a rack. Wet stacking traps moisture and encourages bacterial growth.
Traps that cost marks
- Saying detergent kills bacteria - it does not.
- Disinfecting before cleaning, or disinfecting a greasy surface.
- Ignoring contact time and concentration.
- Confusing pest proofing with pest eradication.
- Using a cloth to dry a supposedly disinfected surface.