An investigation is underway after a horrifying video circulated on social media, appearing to show a McDonald’s worker putting fries in her mouth and then adding them to a box for a customer. The worker at a McDonald’s in Southbridge, Massachusetts , took a fistful of salty fries, shoved them into her mouth and then put them into the iconic red fry box, according to the video that went viral last week. One co-worker was apparently filmed laughing as she held the fry box. “I think it’s crazy that people are messing with other people’s food,” one local told Boston 25 News . “I thought it was disgusting, honestly.” The Southbridge Police Department said in a statement that it was “aware of a video circulating online involving an employee at a local fast food restaurant allegedly contaminating food before it was served.” The department, which didn’t name McDonald’s specifically, said it was investigating the incident alongside health officials and restaurant management.…