It’s human meat.

The Richard Scarry universe is actually set in a twisted dystopian future where animals gained sentience and overthrew the humans. We are the farm animals. I won’t go into where their milk comes from.

The taste of toothpaste lingers for a while and ruins the flavor of breakfast, especially orange juice.

The Way™ is Coffee/tea/juice to temporarily overwrite that morning breath feeling, then breakfast, then brushing teeth.