What should you not do when handling food to control contamination?

There are too many "don't do" things to mention. The largest threat to health and safety while cooking is cross contamination so don't allow cross contamination during your food prep. That means keep raw foods separated from cooked foods both during storage and preparation. Don't use the same tools (knives, cutting boards, tongs, mixing spoons, etc) to prep your salad that you used to prep your raw meat and don't use the same tools that you used to prep the raw meat for serving the cooked meat. Also don't use the same tools for one raw meat that you used to prep a different raw meat, i.e. don't cut a chicken then use the same knife and cutting board for beef without cleaning them first. Wash your hands after handling raw meat or other proteins before doing anything else. Clean and sanitize your workspace after prepping raw proteins before doing anything else. Wash your hands. Wash your hands. And, don't forget to wash your hands often.

Use water as hot as is comfortable to you, use soap, scrub for 30 seconds, don't forget your wrists, back of hands, and fingernails, rinse your hands and dry with a clean, unused cloth towel or paper towels. I advise using paper towels instead of cloth towels because there is a smaller risk of using a paper towel to dry your hands that someone else used to wipe up after prepping raw meat.