The history and legacy of ancient dairying bacteria

Microbes and bacteria are far from enjoying a good reputation in the modern societies of the 21st century. Nevertheless, they play a vital role in our daily lives and culinary practices. For without yeasts and bacteria, a large number of our most popular food products, such as bread, cheese or beer, would not even exist. The manufacturing of dairy products, in particular, avails itself of an immense bandwidth of different bacteria which, in turn, ensure the unmistakeable flavours, textures and aromas.

Although lactic bacteria play such an important role in our contemporaneous cuisine and nutrition, we know very little about their origins and evolution through time. And yet, the exploration of the history of lactic bacteria is excellently suited to gain new insights into human evolution and cultural development: When and where did humans start to incorporate milk into their diets and to manufacture dairy products systematically? When and how did modern humans develop the ability of digesting milk (lactase persistence), and which role did microbes and lactic bacteria play in this context? What similarities and differences are there among the different regions of the world?  

As a result of industrialisation and global food production, we are currently witnessing the rapid disappearance of many traditional methods of manufacturing dairy products. This goes hand in hand with a form of "microbial extermination" of many of the traditional strains of dairying bacteria which will be irrecoverably lost for future research and use.  

The project of the Max Planck Institute for the Science of Human History, entitled "Heirloom Microbes: The History and Legacy of Ancient Dairying Bacteria", sets out to counteract this trend by identifying the microbes still used in traditionally made dairy products in three world regions – Europe, Central Asia and the Middle East – and by examining them for their nutritional value. Subsequently, these traditional "heirloom microbes" will continue to be studied genetically, cultivated and stored in microbial "culture banks" where they will remain saved for future studies and utilizations.

Moreover, the project sets out to explore the role of milk products in human evolution in the three different world regions. The aim is to shed light on how (culinary) culture and genetics interacted as well as on the role played by microbes in the genetic development of lactose tolerability, for example. In order to explore this aspect, the most recent innovations in archaeological research, particularly new technologies serving to identify milk and protein traces in finds of ancient tooth tartar (dental calculus) and objects, will be used. These traces will subsequently be studied with a view to understand how and why milk and dairy products have modified the human genome so successfully in many regions of the world.

From the conceptional and methodical viewpoint, the project combines four very different disciplines by tradition rarely interacting in this constellation: archaeology, microbiology, nutritional science and cultural anthropology; it is of great importance for elucidating microbial diversity today and in the distant past. Furthermore, it will provide important insights into human evolution and the cultural history of dairy products in Europe, Asia and the Middle East, thus improving our understanding of the interaction between (culinary) culture, biology and society.

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