BySHIR PERETS, REUTERS

Scientists told AFP they have baked sourdough bread using yeast found growing in the guts of a frozen mummy.

The frozen mummy in question is Oetzi the Iceman, who lived over 5,300 years ago and was killed on the border of Austria and Italy by an arrow in his back.

He was found by two German hikers in the Alps in 1991 and has been kept at the same minus six degrees Celsius since.

Earlier this month, an Italian team of researchers published in the Microbiome journal that they had found evidence of both ancient and modern microbial life still active in the body.

"His body hosts living, metabolically capable organisms that are actively responding to their environment," Sarhan told Reuters. 

A man takes pictures of a statue representing an iceman named Oetzi, discovered on 1991 in the Italian Schnal Valley glacier, is displayed at the Archaeological Museum of Bolzano on February 28, 2011 during an official presentation of the reconstrution.
A man takes pictures of a statue representing an iceman named Oetzi, discovered on 1991 in the Italian Schnal Valley glacier, is displayed at the Archaeological Museum of Bolzano on February 28, 2011 during an official presentation of the reconstrution. (credit: Andrea Solero/AFP via Getty Images)

"The cold-adapted yeasts are growing. Certain bacteria have colonized and persisted across his tissues for decades. The mummy is, in a very real sense, a living biological interface - a meeting point between the ancient world and the present, where microbes from 5,000 years ago coexist with organisms that arrived last decade."

For archaeology and human history, Sarhan said, the ancient gut bacteria provide ​a rare window into the intestinal ecosystem of a Copper Age human - before industrialization, antibiotics, and processed food transformed human microbiomes, the collection of microbes that naturally live in and on the body.

For conservation science, Sarhan said, the discovery that cold-loving yeasts are actively growing on Oetzi raises questions about the mummy's long-term integrity.

What matters most: How was the sourdough?

"If you tell anyone you have yeast, they immediately ask: Can we use it for bread?" Sarhan said it didn’t work immediately, but after three months of consistent work, the team "had a very, very good sourdough."

Sarhan also told AFP the team would consider using the yeast to brew beer, but the published study focused on more serious uses for their discovery.

The researchers identified which microbes were present during Oetzi's lifetime and which colonized his body post-mortem. After death, the ​glacier environment introduced its own ⁠microbial community to his body - cold-tolerant bacteria and yeasts from the surrounding ice and soil.

Microbes found exclusively in deep internal tissues, showing high DNA damage, were almost certainly present during Oetzi's life or shortly after, Sarhan said.