McDonald's doesn't exactly have the best reputation for beef quality but if you were expecting to find ammonia-drenched, gut particle-filled pink slime sludge goop de loop, well, you're going to be disappointed. It's all beef. You can see how they make it above.
They combine lean beef and fattier beef in their burger blends and then freeze the patties to maintain the consistency. It's obviously not fresh from the farm beef but for McDonald's? Not bad. I've got to hand it to McDonald's Canada's YouTube account -- they're not afraid to answer the tough questions with real answers. Transparency and all that. Pretty good when it comes to food. [McDonald's Canada]
Oz ed note: We've actually known this for quite a while in Australia.