The patties in McDonald's hamburgers belong to "synthetic meat", which is made of different kinds of meat and then processed and spliced to make a patties again. "Synthetic meat" is generally based on pork, chicken and beef, plus starch. Synthetic meat is cheap, so it is widely used in fast food, canned food, ham sausage and other foods.

Another netizen replied that it was 100% beef. I really think that man is mentally retarded. Do you know how expensive beef is? A hamburger at McDonald's costs more than 20 yuan. Do you still want to eat beef? Do you think it's a charity?

And McDonald's advertisements have never mentioned that it is 100% pure beef. He just said "Niu Bao". Even if there is only 1% beef in "Niu Bao", it can be called "Niu Bao", and the advertisement is just picking words.