McDonald's has issued an apology after some of its customers took to social media to complain about a key ingredient missing from the mozzarella cheese sticks they had purchased.



Some customers' cheese sticks lacked cheese.



NBC News reached out to McDonald's for a statement, and the company said: "In these instances, we believe the cheese melted out during the baking process in our kitchens and shouldn't have been served. We apologize to any customers who may have been affected. We are working to fix this in our restaurants."