https://www.nytimes.com/2019/08/08/science/egyptian-yeast-bread.html
The yeast for this bread was extracted from an ancient Egyptian loaf that had been buried beneath a temple during the Middle Kingdom.Maximilian Blackley
Mr. Blackley also had a sample of actual bread from the Middle Kingdom, which came from the site of a mortuary temple for the pharaoh Mentuhotep II and is now at the Museum of Fine Arts. “There were three loaves there, as offerings, and the building was built on top of it,” Dr. Love said.