What Is Cross-Contamination and How Can You Prevent It?

Cross-contamination occurs when harmful bacteria, allergens or other contaminants are transferred from one surface, food or person to another. It’s one of the leading causes of food-borne illness in Australia and can happen easily if proper hygiene and food handling practices are not followed.

What is cross-contamination?

In the context of food safety, cross-contamination refers to the transfer of harmful microorganisms or allergens from one substance or object to another. This usually occurs when bacteria from raw food, such as poultry or seafood, comes into contact with ready-to-eat food, utensils or surfaces without proper cleaning and sanitising taking place in between.

Even small amounts of bacteria like Salmonella, E. coli or Listeria can cause serious illness. In a food business, this can lead to customer complaints, a food-borne illness outbreak, increased health inspections, or even closures.

Why cross-contamination is a serious risk in Australia

Cross-contamination is one of the main causes of food poisoning in Australia. Each year, an estimated 4.1 million Australians suffer from food-borne illness, and many cases can be traced back to poor food handling or inadequate cleaning and sanitising between tasks.

Under the Food Standards Code, all food businesses must take reasonable steps to prevent contamination. This means having trained staff, proper cleaning and sanitising procedures and food safety systems in place to protect public health.

Common causes of cross-contamination

There are several ways cross-contamination can occur during food preparation and service:

• Using the same chopping board for raw meat and vegetables without washing it properly
• Handling money or phones while preparing food
• Storing raw food above cooked food in the fridge
• Reusing wiping cloths or sponges without sanitising them
• Touching ready-to-eat food without gloves, or with unwashed hands

Tip: Colour-coded chopping boards and utensils help prevent cross-contamination between raw and cooked foods.

How to prevent cross-contamination in the kitchen

Handling raw and cooked foods safely

Always separate raw foods from ready-to-eat foods, and use different utensils and equipment for each type. Store raw meats on the lowest shelf of the fridge to prevent drips from contaminating other items.

Cleaning and sanitising surfaces

Clean and sanitise all benches, knives and cutting boards after each task. Use food-grade sanitisers and allow surfaces to air dry for maximum effectiveness. Replace cloths and sponges frequently, as they can harbour bacteria.

Personal hygiene and personal protective equipment (PPE)

Wash hands thoroughly with warm, soapy water for at least 20 seconds before and after handling food. Wear gloves when appropriate, and replace them when switching between food types. Avoid touching your hair, face or phone while preparing food. 

Wear a clean apron or chef’s jacket to create a hygienic barrier between your everyday clothing and the food you’re preparing.

Cross-contamination vs cross-contact (for allergens)

While cross-contamination involves bacteria, cross-contact occurs when trace amounts of an allergen (such as peanuts, gluten or milk) come into contact with food that shouldn’t contain it. For someone with a severe allergy, even a tiny amount can cause a serious reaction.

To prevent cross-contact:

• Clean utensils, benches and equipment thoroughly after each use
• Store allergen-containing foods separately
• Train staff to understand and manage food allergens safely

How training helps prevent cross-contamination

Training helps Food Handlers understand how and why cross-contamination occurs, and how to stop it. Programs like the Food Safety Supervisor course and Food Handler course teach practical hygiene and safety practices that can be applied immediately in the workplace.

Reminder: Whether you work in hospitality, retail, food processing or healthcare, everyone who handles food has a role in keeping customers safe.

Frequently Asked Questions

Q. What are the three types of food contamination?

1. Physical (foreign objects)
2. Chemical (cleaning agents or pesticides)
3. Biological (bacteria or viruses)

Q. Can cross-contamination happen in a fridge?

A. Yes. Storing raw food above cooked or ready-to-eat food allows juices to drip and spread bacteria.

Q. What’s the best way to clean and sanitise surfaces?

A. Wash with warm, soapy water, rinse, then sanitise using a food-safe sanitiser. Let surfaces air dry.

Q. Is glove use enough to prevent contamination?

A. No. Gloves must be changed between tasks, and hands should be washed before putting them on.

Q. Who is responsible for preventing cross-contamination?