Yeah, drag to trash was my first try, hence why I put it in the world to begin with. Unfortunately, hovering on it doesn't give a hand, just a mouse pointer with the option for a Sim to "Throw Out" (which doesn't work).
The object itself seems to be bugged. Since it's not a finished food item (like "plate of hamburgers") I suspect that the food was cooking on the grill WHEN it was initially moved to inventory. This separated it from its action object (the grill) before it was an "interactable" independent object, and hence the glitch. Mark down another one for EA to fix at some point. ;)
ETA - FWIW, this could have been fixed in older Sims by using the moveobjects cheat, which is disabled in S4.