Fast-food giant McDonald’s serves thousands, if not millions, of burgers worldwide. For a long time, rumors floated around where their burger patties originated, but McDonald’s has long put those rumors to rest.
According to its website, McDonald's meats are 100% beef, a ground-up mixture of chuck, sirloin, and round. The company buys from ranchers all over the United States and overseas, such as Oklahoma City-based Lopez Foods, which has supplied beef, pork, and chicken to the Golden Arches since 1968.
In one of McDonald's largest meat processing facilities in Germany, Business Insider noted that they first check on beef shipments to ensure no bones nestled within before putting them through a giant meat grinder to form patties. The burgers are then flash-frozen and packed into plastic bags and boxes for shipping.
In a recent change for McDonald's, if you order a Quarter Pounder, there's a good chance your burger patty is fresh and not previously frozen (via CNN). As for it being completely grass-fed, the cattle might start out eating grass, but they're then moved over to a diet of grains, grasses, and minerals.