Switching from frozen to fresh beef signals the importance McDonald's places on moving toward fresher ingredients as consumers demand them. It already has made moves to clean up other parts of its menu, including removing antibiotics from chicken and preservatives from chicken nuggets. It's also made changes to its burgers to make them taste better, like searing them longer and toasting buns. Its fresh and frozen burgers are both 100 percent beef without fillers, additives or preservatives, McDonald's said.