Contamination by bacteria occurs because of improper handling of raw food.
Step-by-step explanation:
Raw foods get easily contaminated if they are kept in a bacterial affected place or are not handled properly. Improper handling means- keeping the food in contact with bacteria affected place or food, unclean chopping board, knife etc.
It is also considered as cross contamination. In this contamination the bacteria gets transported from raw food to other food or a person’s body. It causes food poisoning that leads to illness in a person.