Cross-Contamination and Its Prevention
How contamination travels
Cross-contamination is the transfer of hazards from a raw or dirty source to ready-to-eat food. It is direct (raw meat dripping onto cooked food) or indirect via hands, knives, chopping boards, cloths, sponges, containers, scales, tap handles, fridge shelving, and pests.
Controls that the exam expects
- Separate raw and cooked preparation: dedicated boards, knives, and benches, ideally colour-coded.
- In the fridge, store cooked and ready-to-eat food above raw meat, poultry, and seafood, each in covered containers on trays.
- Wash and sanitise hands, equipment, and surfaces between raw and ready-to-eat tasks.
- Use separate or freshly sanitised cloths; replace wiping cloths frequently and never use one cloth across raw and cooked zones.
- Never reuse containers that held raw food for cooked food without cleaning and sanitising.
- Keep wash-up and handwash sinks separate from food-prep sinks.
- Cover food; keep it off the floor; protect from drips and condensation.
- Control pests and exclude them from food areas.
Worked example
A kitchen uses one board to cut chicken, wipes it with a cloth, then slices cooked beef for a buffet. Salmonella from the chicken moves via board and cloth to the beef, which will not be cooked again. Correct practice: switch to a sanitised board, or use a colour-coded cooked-food board, and change to a clean cloth. The mistake is not the wiping - it is wiping without cleaning and sanitising.
Traps that cost marks
- Storing raw chicken above cooked rice in the fridge.
- Rinsing a board with water only and calling it sanitised.
- Using the same cloth for benches and hands.
- Thinking cross-contamination only happens through hands.
- Placing cooked food in a container that held raw meat, even briefly.