He smiles a little bit and beckons her over to the fridge before opening the door and he stuck his hand in and then made a beckoning motion. She should try it.

"Tuna mayo." He says conversationally, even though he knows she can't understand that yet. The air inside is cold, and the food he has in there makes it obvious he's using it to store food so it doesn't go bad.

It's not a novel invention to him, but it's probably an important one.