As of 2014, McDonald's claims to use pure beef along with ketchup and seasonings to make its burgers. Until 2012, according to ABC News, McDonald's used a beef product in burgers treated with ammonium hydroxide to kill bacteria like E. coli. This product is only used for pet food in the United Kingdom and is often referred to as pink slime in the United States.
The ingredients that are in these products cause concern to health-conscious people. Much of the beef used in the United States still contains pink slime, and consumers want to know where McDonald's gets its beef.
Many ingredients in condiments and buns are known to cause obesity and are even toxic. BHT, which is used in the buns of burgers, is toxic to the brain and nervous system. Potassium sorbate, found in McDonald's pickles, is linked to studies that show damage to human genetic material. When genetic material is damaged, diseases such as cancer occur. McDonald's ketchup contains MSG, which is used in lab tests to create obese animals for testing.
McDonald's own website has a tool that allows consumers to see what ingredients are included in each burger. Clicking the ingredient itself allows consumers to see what is in that ingredient specifically.