Shake Shack

[Rich]

You should never entertain medium rare burgers r. It's all to do with minced meat.This is because bacteria, such as salmonella, listeria and e-coli, lives on the outside of meat so searing steaks and cuts of beef and lamb would kill anything harmful, even when it's still pink inside.
But as burgers are minced up those bugs that were on the outside are then on the inside and therefore should be cooked thoroughly.

Nope. So long as the meat is heated to 120F throughout, all the bacteria will be dead.

[7sisters]

Nope. So long as the meat is heated to 120F throughout, all the bacteria will be dead.

Well, you may want to put your faith in fast food establishments to actually carry that out but I'd prefer to play safe.