It has been a long time since I worked at Mickey D's, but my recollection is that if he's on break and wants food he's supposed to go to the counter to order. I would also have assumed "What's fresh?" means "What's up?" in this situation.
But it's also, like, not that bad? Unless coworker also has an awkward moment, the conversation presumably continues "Not much, I'm on break, what do we have that's ready?" and then you tell him.