I teach food safety and fell this advise from the FSA is helpful
Burgers aren’t like steaks
Unlike steaks, rare burgers prepared at home can cause serious food poisoning. Steaks can be served pink as they’re only ever contaminated by bacteria on the outside. In burgers bacteria from the outside of the raw meat are spread all the way through when it’s minced and are not killed if burgers are not cooked all the way through.
So cook your burgers thoroughly this BBQ weekend and help us spread the word to keep your loved ones safe.