McDonald's customers upset over mozzarella sticks that lack a key ingredient

First it was Internet outrage over the Reese peanut butter Christmas trees that didn't look like Christmas trees. Now it's cheese-less cheese sticks.

Dozens of McDonald's customers on social media are complaining that the restaurant's mozzarella sticks are missing the cheese.

The new menu item was recently launched at McDonald's as part of its "McPick 2" menu. But customers have been tweeting photos of their orders and displeasure at the lack of cheese.

McDonald's issued a statement on Thursday:

"We are aware of a low volume of guest concerns about our Mozzarella Cheese Sticks," spokeswoman Lisa McComb said in an emailed statement. "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."