Cross-Contamination Prevention
Cross-contamination is the transfer of pathogens from raw food, hands, equipment or pests to ready-to-eat food. The exam tests whether you can spot the transfer route in a scenario and name the control.
Main routes
Hands; knives, boards and utensils; wiping cloths; containers and trays; drip from raw meat stored above; splashing from sinks; insects and rodents; shared sinks or storage areas.
Controls in the kitchen
- Store raw meat, poultry and fish below cooked and ready-to-eat food, covered, on the bottom shelf.
- Use separate or colour-coded boards and knives for raw meat, cooked food and salads.
- Clean and sanitise equipment between raw and ready-to-eat tasks – do not just wipe it.
- Never return cooked food to the tray that held it raw.
- Never reuse marinade unless it is boiled; keep a separate basting portion.
- Use a clean cloth for each task and store wiping cloths in sanitising solution.
- Do not wash raw chicken – splashing spreads Campylobacter across surfaces.
- Change gloves and wash hands between tasks; gloves get as dirty as hands.
- Store food only in food-grade containers, never in chemical or paint containers.
Separation of areas
Keep raw preparation away from ready-to-eat preparation where possible, and keep washing-up water and waste away from food preparation.
Worked example. A handler cuts raw chicken on a board, wipes the board with a damp cloth, then chops cucumber for a salad. Reasoning: the cloth spreads chicken juices, and wiping removes visible soil but not bacteria; the cucumber is eaten raw, so nothing later destroys the organisms. Correct action: scrub the board with hot water and detergent, rinse, sanitise with a 100 ppm chlorine solution or 77 °C water, air-dry, then use a clean board.
Traps. A wet cloth is a contamination tool, not a cleaning tool. Refrigeration does not stop cross-contamination. Gloves that have touched raw meat are as dirty as bare hands.