What did archeologists find in Bimbo's mouth in the story Dog of Pompeii?

In the story "Dog of Pompeii" by Louis Untermeyer, archaeologists discovered a small, charred dog lying beside a boy in the ruins of Pompeii. The dog, named Bimbo, was found with its mouth open, which had a piece of bread inside. This poignant detail highlights the bond between the dog and its owner, illustrating themes of loyalty and sacrifice amidst the tragedy of the volcanic eruption.