The Origins of Kefir Cheese was Not 'With Love From Russia' But from Somewhere Else, Says Scientist
It would be a hard task to find anyone who does not know what cheese is. However, the question about the origin of these beloved food items may not garner many answers. A recent study published on Cell shed light on the history of one popular variety of these edibles.
The variety that is at focus in the study is Kefir cheese. For the examinations, researchers analyzed samples they unearthed beside the Tarim Basin mummies in China. As per analysis, the specimens were around 3,600 years old. This makes it the oldest known cheese sample in the world, according to researchers.
Experts are hopeful that further analysis will give them insights into the eating habits of humans at that time. "This is the oldest known cheese sample ever discovered in the world," said Qiaomei Fu, the paper's corresponding author at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, stated Science Daily. "Food items like cheese are extremely difficult to preserve over thousands of years, making this a rare and valuable opportunity. Studying the ancient cheese in great detail can help us better understand our ancestors' diet and culture."
Around two decades ago the samples were uncovered by archaeologists on the heads and necks of the mummies present inside the Xiaohe cemetery. Initially, experts thought that it was a fermented dairy product, but did not have any idea on what exactly it was. After some years, researchers managed to extract DNA samples from specimens picked up from three different tombs and identified cow and goat DNA in them. From the specimens, researchers figured out that Xiaohe people used different kinds of milk for different batches of cheese. This was different from what was observed in Middle Eastern and Greek cheesemaking.
The microorganisms found in the cheese confirmed to researchers that it was of kefir variety. The team located Lactobacillus kefiranofaciens and Pichia kudriavzevii in the samples, that are found in present-day kefir grains. The sequencing of bacterial genes from the samples helped experts track how the probiotic microorganisms evolved over the years. The study specifically concentrated on Lactobacillus kefiranofaciens and described the difference between its ancient and modern variants.
Modern-day Lactobacillus kefiranofaciens are mainly divided into two types, originating from two countries respectfully, Tibet and Russia. The bacterial genomes located on samples of Xiaohe cemetery were close in resemblance to the Tibetan varieties. "Our observation suggests kefir culture has been maintained in Northwestern China's Xinjiang region since the Bronze Age," Fu said. This challenged the previously held popular assertion that cheese spread earlier from the Northern Caucasus in modern Russia to other parts of Europe and beyond.
Modern-day Lactobacillus kefiranofaciens were found to be less likely to trigger an immune response in human intestines. This implied that adaptations undertaken by the bacteria made it more suitable for human hosts. The study also showcased how Lactobacillus kefiranofaciens interchanged genetic material with associated strains, to improve its stability and fermentation potential over time. "This is an unprecedented study, allowing us to observe how a bacterium evolved over the past 3,000 years. Moreover, by examining dairy products, we've gained a clearer picture of ancient human life and their interactions with the world," Fu explained. "This is just the beginning, and with this technology, we hope to explore other previously unknown artifacts."