Before you start cooking, you should technically start cooking after you wash your hands with water and soap. This is meant to kill the bad bacteria - or at least most of it - that you won’t have a serious risk of transferring something to your food that won’t be killed during cooking. Many people don’t do this at home - and I’m certainly guilty of it more often than not.
However, if you’re working with raw meat of any kind (be it beef, chicken, or otherwise), this is especially important. Meats, when improperly stored, can be a breeding ground for dirty bacteria that’ll make you sick. One such example is E. Coli. This is mainly found on chicken that is stored in a fridge that is too warm.