The transfer of harmful bacteria, allergens or other hazards from one food, surface or person to another.
The transfer of harmful bacteria, allergens or other hazards from one food, surface or person to another. Cross-contamination is the spread of a hazard from a contaminated source to food that is otherwise safe. It commonly happens when bacteria move from raw food (such as raw meat, poultry, seafood or eggs) to ready-to-eat food via hands, chopping boards, knives, cloths or work surfaces. It can also involve transferring allergens from one food to another, which is a serious risk for people with food allergies. There are three main routes: food-to-food (for example raw juices dripping onto cooked food), equipment-to-food (using the same unwashed utensils or surfaces), and people-to-food (unwashed hands or dirty clothing). Because the transferred hazard is often invisible, cross-contamination is one of the leading causes of foodborne illness and allergen incidents in food businesses. Australian food businesses prevent cross-contamination by separating raw and ready-to-eat foods, using dedicated or colour-coded boards and utensils, storing raw meat below and away from ready-to-eat food in the fridge, and cleaning and sanitising surfaces between tasks. Good hand hygiene and clean uniforms stop handlers from spreading bacteria. For allergens, the same principle applies as allergen cross-contact: use clean equipment, prepare allergen-free orders carefully, and avoid shared utensils that could carry traces of a declared allergen. Standard 3.2.2 requires businesses to take practicable measures to protect food from contamination, and a food safety program should identify the points where cross-contamination is most likely. A deli worker slices raw bacon and then, without cleaning the slicer, uses it to slice ready-to-eat ham. Bacteria from the raw bacon transfer to the ham, which customers eat without further cooking. Cleaning and sanitising the slicer between the raw and ready-to-eat products, or slicing ready-to-eat items first, would have prevented the contamination.
Frequently asked questions
What are the main types of cross-contamination?
Food-to-food (such as raw juices dripping onto cooked food), equipment-to-food (shared unwashed utensils or surfaces), and people-to-food (unwashed hands, hair or dirty clothing).
How do colour-coded chopping boards help?
Assigning different coloured boards to different food types, such as raw meat and salads, makes it easy for staff to avoid using the same board for raw and ready-to-eat foods, reducing the chance of transferring bacteria.
Is cross-contamination only about bacteria?
No. Allergen cross-contact is also a form of cross-contamination, where traces of a food allergen transfer to a dish meant to be free of it. This can cause a serious reaction in a sensitive customer.
How should raw and cooked food be stored to prevent cross-contamination?
Store raw meat, poultry and seafood in sealed containers on the lowest fridge shelves, below ready-to-eat foods, so juices cannot drip onto food that will not be cooked again.
Does washing hands really make a difference?
Yes. Hands are one of the most common ways bacteria and allergens move between foods. Washing hands thoroughly at the right times is one of the simplest and most effective controls.
