What kind of household pest would eat HALF a loaf of bread after chewing a 1.5" hole in the plastic cover?

Today, I found that the wrapped loaf of white bread in our pantry was mauled. About half of it was missing, and presumably eaten by something. Closer inspection revealed a 1.5" hole in the plastic bag on the bread (GROSS). Is this a mouse? Roaches? I haven't found any pests or droppings of any kind in my house, and we don't have pets. The bread was stored off the floor on a shelf in our pantry. No other food appears to have been similarly affected. I am so grossed out and want to prevent this from happening again.