McDonald's burgers are made from the same meat as hamburger you get in major restaurants, if not even higher quality.

There was a high profile case against what they called pink slime in the news but it was settled out of court and ABC News paid a fairly high settlement fee.  The meat made with that by-product was used in institutional foods and while it was not 100% beef, it was not dangerous either. That's why there is a libel suit filed.  That's not to say everyone is honest with their food production. I've seen stuff that would make you not want to eat.  There was a major hearing again today over a case known as PCA of America. Which is over peanut butter that killed numerous people.
Of all the bad things I've seen, the only adjustment I have ever made is to never eat hamburger less than medium well. Hamburger is among the most dangerous foods because of the way it's processed. Not because of the meat per se but because of the potential for pathogen contamination.