Quarter Pounders, at least now, are supposedly the only hamburger at McDonald’s that are fresh ground beef and cooked in the restaurant. All the other burger meat is pre-cooked and just warmed up.
No telling what they used to be or what preservatives are used - probably embalmed cattle or something.
McDonalds actually wanted to intro a 1/3 pounder but the average bonehead didn’t know that 1/3 is bigger than 1/4. True story