Cross-contamination is when bacteria spread between food, surfaces or equipment. It is most likely to happen when
So, if raw meat drips onto a cake in the fridge, bacteria will spread from the meat to the cake.
If you cut raw meat on a chopping board, bacteria will spread from the meat to the board and knife. If you then use the same board and knife (without washing them thoroughly) to chop a cucumber, the bacteria will spread from the board and knife to the cucumber.
Hands can also spread bacteria. If you touch raw food and don’t wash your hands thoroughly you can spread bacteria to other things you touch.
By avoiding cross-contamination, you can stop bacteria spreading.
An easy way to prevent cross-contamination is to use different chopping boards and different knives for raw and ready-to-eat food. Try using one colour for chopping boards and knives used with raw food and another colour for those used with ready-to-eat food.