Preventing Cross Contamination in Commercial Kitchens

Cross contamination is one of the leading causes of food poisoning outbreaks. It occurs when harmful microorganisms, allergens, or foreign objects are transferred from one food, surface, or person to another. Understanding and preventing cross contamination is essential for any food business.

Types of Cross Contamination

Cross contamination can occur in several ways:

Direct Contamination

When contaminated food touches another food directly. For example, raw chicken dripping onto ready-to-eat salad, or storing uncovered raw meat above cooked products in a fridge.

Indirect Contamination

When contamination is transferred via an intermediate surface, equipment, or hands. This is often more insidious and harder to detect. Examples include using the same chopping board for raw meat and vegetables, or handling raw products then touching door handles.

Allergen Cross-Contact

When foods containing allergens come into contact with allergen-free foods. Even trace amounts can trigger severe reactions in sensitive individuals. This requires particular attention as allergens aren't destroyed by cooking.

High-Risk Situations

Be especially vigilant in these common cross contamination scenarios:

• Handling raw meat, poultry, or fish

• Using shared equipment or surfaces

• Working in cramped spaces with limited preparation areas

• During busy service periods when shortcuts are tempting

• When receiving and storing deliveries

• Preparing foods containing major allergens

Control Measures: Separation

Physical separation is the most effective way to prevent cross contamination:

• Use separate fridges for raw and cooked foods where possible

• Store raw meat on the lowest shelves, below ready-to-eat foods

• Use colour-coded chopping boards (red for raw meat, blue for fish, green for vegetables, yellow for cooked meat, white for dairy)

• Designate specific equipment for allergen-free preparation

• Create separate preparation areas for raw and cooked foods

• Schedule preparation of allergen-containing foods at different times

Control Measures: Cleaning

Effective cleaning removes contamination from surfaces and equipment:

• Clean and disinfect surfaces between tasks, especially after handling raw foods

• Use appropriate sanitisers — check they're food-safe and used at correct dilution

• Follow the two-stage process: clean to remove visible dirt, then disinfect

• Pay attention to handles, taps, and other frequently touched surfaces

• Clean equipment thoroughly, including blades, seals, and hard-to-reach areas

• Change cloths regularly and avoid using the same cloth for different tasks

Control Measures: Personal Hygiene

Food handlers are a major vector for cross contamination:

• Wash hands thoroughly and frequently, especially after handling raw foods

• Change gloves between tasks — gloves don't replace handwashing

• Wear clean protective clothing

• Tie back hair and avoid touching face or hair while working

• Don't work with food when suffering from diarrhoea or vomiting

• Cover cuts and sores with waterproof, brightly coloured plasters

Workflow Design

Good kitchen design helps prevent cross contamination:

• Arrange workflow to move from raw to cooked (linear flow)

• Avoid backtracking through the kitchen

• Position handwash basins conveniently near food preparation areas

• Ensure adequate space for separate preparation activities

• Design storage to facilitate proper separation

Key Takeaways

• Cross contamination transfers hazards between foods, surfaces, and people

• Separation, cleaning, and personal hygiene are the main control measures

• Use colour-coded equipment to prevent confusion

• Clean and disinfect between tasks, especially after raw food handling

• Good kitchen design supports contamination prevention

• Allergen cross-contact requires special attention