Researchers studying exceptionally well-preserved feces found in Iron Age salt mines have discovered the presence of fungi used in food fermentation. The findings indicate the miners were feasting on blue cheese and beer around 2,700 years ago.
The study, published in the journal Current Biology, reports on several paleofeces samples found in a World Heritage site in Austria known as the Hallstatt salt mines. The unique environmental condition of the mines – constant mild temperatures with high salt concentrations – are ideal for preserving the ancient poo allowing researchers valuable insights into the diet and gut microbiome of Iron Age people.
“Molecular and microscopic investigations revealed that the miner’s diet was mainly composed of cereals, such as domesticated wheats (emmer and spelt), barley, common millets, and foxtail millets,” the researchers write in the study. “This carbohydrate-rich diet was supplemented with proteins from broad beans and occasionally with fruits, nuts, or animal products.”
Because the Hallstatt salt mines were consistently occupied for over two millennia researchers are afforded the unique opportunity to study gut microbiome changes in human populations over long periods of time. Here, the researchers discovered remarkable consistency in the miners’ diet up to the 18th century.
Perhaps one of the more notable differences between between the Iron Age miner diet and their 18th century counterparts is the form in which cereals and legumes were consumed. The researchers propose the more ancient miner diet consisted of eating these grains in a sort of porridge or gruel, while more recently the miners consumed processed grains in the form of breads and biscuits.
The most surprising finding in the study was the discovery of specific fungi DNA in the paleofeces samples. Penicillium roqueforti and Saccharomyces cerevisiae DNA were detected indicating consumption of fermented foods and drinks.
Penicillium roqueforti is particularily used in the creation of blue cheese and the study points out this is the earliest evidence of this kind of cheese production in Europe. Saccharomyces cerevisiae is a yeast used to ferment alcohol and alongside the presence of several grains the researchers hypothesize it was used here to make beer.
“Genome-wide analysis indicates that both fungi were involved in food fermentation and provide the first molecular evidence for blue cheese and beer consumption during Iron Age Europe,” says Frank Maixner, an author on the new study. “The Hallstatt miners seem to have intentionally applied food fermentation technologies with microorganisms which are still nowadays used in the food industry.”
The study adds to our understandings of historical food production, suggesting dietary practices thousands of years ago were much more mature than previously assumed. The new research also demonstrates increasingly sophisticated paleofeces microbiome analysis techniques allowing for detailed insights into the gut microbes of our ancient ancestors.
“These results shed substantial new light on the life of the prehistoric salt miners in Hallstatt and allow an understanding of ancient culinary practices in general on a whole new level,” notes Kerstin Kowarik, another author on the new study from the Museum of Natural History Vienna. “It is becoming increasingly clear that not only were prehistoric culinary practices sophisticated, but also that complex processed foodstuffs as well as the technique of fermentation have held a prominent role in our early food history.”
The new research was published in the journal Current Biology.
Source: Cell Press
