Cross-Contamination Prevention and Control
Sources of cross-contact
Allergen cross-contact occurs when an allergen is unintentionally transferred to an allergen-free food. Common sources: shared equipment (knives, boards, tongs, fryers, grills, mixers), shared surfaces, hands and gloves, cloths and sponges, aerosols and dust (flour, powdered milk), shared oils and water, condiments and garnishes, and storage where open ingredients sit together.
Controls
Apply segregation (separate areas, equipment, colour-coded boards), cleaning and disinfection validated for allergen removal (detergents and physical removal, not just sanitiser), dedicated utensils, handwashing before and after handling allergens, covered storage, and scheduling (prepare allergen-free dishes first or in a clean area). Understand that cooking does not destroy allergens and that frying oil can carry allergens (e.g. battered fish then chips).
Traps
- A sanitiser alone may not remove protein; physical cleaning matters.
- Shared fryers and shared grills are classic exam scenarios.
- Gloves do not prevent cross-contact if the same gloves touch multiple foods.
- 'Picking out' an allergen (e.g. removing nuts) does not make food safe.
Rule of thumb
If an allergen-containing food and an allergen-free food share any surface, tool, oil, water or hand, assume cross-contact unless a validated control (segregation or cleaning) is in place.