Food fermentation was apparently already the order of the day.

Human excrement normally doesn’t last long – why would you want to? – and certainly not for thousands of years. Of course there are always exceptions to the rule. One example is human feces found in prehistoric salt mines, located in the Austrian UNESCO World Heritage Site of Hallstatt-Dachstein/Salzkammergut. Researchers are now looking into this ancient human poo. And that leads to a surprising discovery.

salt mines

Salt mining began in the beautiful landscape of the Salzkammergut as early as the Middle Bronze Age. Salt was a very valuable commodity at the time and it is believed that the area flourished thanks to the salt mines. The special conditions in the salt mines also ensured that, among other things, leather and textiles, but also human poo, for example, have withstood the test of time. Previous studies had already shown that ancient excrement found in salt mines could provide important insights into early human nutrition and health. And so researchers decided to subject the feces found in the Austrian salt mines to a thorough inspection.

The poo samples from the Hallstatt salt mines studied in the study. Image: Eurac Research/Frank Maixner

The researchers took a closer look at the microbes, DNA and proteins hidden in the 2,700-year-old fecal samples. Thanks to these in-depth analyses, the team then managed to reconstruct the diet of the people who lived around the salt mines at the time.

Diet

The researchers found that bran and calyx of various grains represent the most common eaten plant remains. This high-fiber, high-carbohydrate diet was then supplemented with protein derived from fava beans, fruits, nuts and animal foods. This means that until the Baroque period, the ancient miners mainly followed a non-Western diet consisting of whole foods, fresh fruits and vegetables.

fungi

While that is of course an interesting discovery, the research only really became spectacular when the team expanded their microbial analysis to include fungi. “We found traces of Penicillium roqueforti and Saccharomyces cerevisiae,” explains researcher Frank Maixner Scientias.nl from. And that’s interesting. These molds are used, among other things, for making blue cheese and beer, respectively. “The molecular traces therefore point to the consumption of fermented foods and drinks in the Iron Age in Europe,” Maixner said.

food fermentation

The researchers now have the first evidence that people already consumed blue cheese and beer some 2,700 years ago, in the Iron Age in Europe. And that means they were already capable of food fermentation back then. “The Hallstatt miners seem to be deliberately applying food fermentation techniques with microorganisms that are still used in the food industry today,” Maixner said. “These results therefore shed a substantial new light on the lives of the inhabitants of the old salt mines.”

This image shows 2,600-year-old human excrement from the Hallstatt salt mines in which beans, millet and barley are clearly visible. Image: Anwora/NHMW

In addition, the findings also provide insight into ancient culinary practices in a more general sense. “It is becoming increasingly clear that these were not only refined, but that complex processed foods and the technique of fermentation played a prominent role in our early food history,” Maixner said.

food history

With this discovery, we are expanding our knowledge of our own food history. And that, according to the researchers, is an important step. “That knowledge is very scarce,” Maixner says. “What we know about it mainly provides insight into the most important nutritional components, but hardly reveals information about the culinary practices. It is therefore fascinating to better understand the composition of historical meals, especially as it provides important information about the life and health of ancient societies.”

The researchers are not yet letting go of the subject. In ongoing and future studies of the human excrement from Austria’s salt mines, the team hopes to learn more about early production of fermented foods. They also want to learn more about the interplay between diet and the composition of the gut microbiome over different time periods.