大约 3600 年前，在今属新疆的中国西北部地区的塔里木盆地，一名年轻女子去世并被安葬。干热环境与密闭棺材保护了她的遗体，所以当考古学家在2003年发现其墓地时，发现了自然防腐的完整尸体，依然身穿毛毡帽、缠边羊毛大衣和皮质靴。
令人惊讶的是，随身还有奶酪块，它们被排列成项链状摆放。
这就是“世界上最古老的奶酪”，来自古生物学研究所副所长、中国科学院古脊椎动物与人类学研究所以及微生物遗传学家 Fu Qiaomei 表示。在周三发表于《细胞》杂志的一篇研究中，Fu 教授领导的团队对塔里木盆地中三具木乃伊颈部散落的奶酪和其中共生菌群进行了基因分析，揭示了它们是如何制成的。
人类对于奶酪的迷恋可追溯到数千年。科学家在 7000 年前的陶器上发现可能来自奶酪的脂肪残留物，并且有苏美尔时期的文献提及这种乳制品；然而塔里木盆地样本是已知最早被科学界认定为奶酪的世界物质。
Fu 教授及其团队从塔里木盆地三具尸体旁边搜集了散落的奶酪碎片，提取并化学分离其中残存的 DNA 片段，并与现代乳制品制作过程中涉及物种的基因组进行了比较。研究发现牛和羊的 DNA 余迹，表明这两种动物的奶均被用于古代奶酪的制备；他们还能追踪到将牛奶发酵成奶酪所需的微生物的 DNA。
研究人员发现了与牛奶一起形成凝块、被称为 kefir 米粒的细菌和酵母菌，这些米粒可用于生产具有酸奶口感的发酵乳制品和柔软酸味的 kefir 奶酪。
对 Fu 教授而言，鉴定古代奶酪产生的微生物物种是“异常激动”的，因为奶酪制作方法可以揭示当时人们的生活方式及其交往对象。将奶酪埋入坟墓表明其珍贵价值，并且混合了多种牛奶来源和使用的细菌类型暗示塔里木盆地、西小河地区以及欧亚草原人民之间的潜在交流。
对于乳制品历史学家、佛蒙特大学食品科学名誉教授 Paul Kindstedt 而言，研究乳制品提供了一种“跟踪”人类文化在语言或文字记载之前进行活动的新途径。他表示自己尚未参与此次新研究，“但这是一个深入了解古代社会生活方式和相互作用关系的创新方式。”
当时埋藏时，这奶酪很可能是柔软且带有一丝丝酸味，与现代 kefir 类似。据 Fu 教授所知，还没有人尝过从墓穴中提取的散落碎片。“我认为人们不想尝试是因为我们看到它并不怎么吸引人。”她说。
如果有机会尝一下，他们可能会感到失望。一些 1930 年代在埃及墓穴发现奶酪并进行采样的考古学家，在 1942 年发表的报告中指出，这“没有气味且仅有尘土般的味道”。
然而，Fu 教授和她的同事渴望根据获取的信息尝试重现这种古代奶酪，“我觉得下一步我们应该制作它。”她表示。
需要补充的是，塔里木盆地的奶酪样本与之前发现的埃及墓穴中的物质进行了对比。通过现代技术分析及研究揭示了它们之间的不同之处。
新闻来源：www.nytimes.com
原文地址：World’s Oldest Cheese Stood Alone for 3,600 Years
新闻日期：2024-09-25
原文摘要：
Around 3,600 years ago, a young woman died and was buried in the Tarim Basin, a desert in what’s now the Xinjiang region of northwestern China. The dry conditions and her sealed coffin preserved her body, so when archaeologists uncovered her grave in 2003, they found her naturally mummified remains, still dressed in a felt hat, tasseled wool coat and fur-lined leather boots. They also found chunks of cheese, laid out like a necklace. This dairy decoration is the “oldest cheese in the world,” said Qiaomei Fu, a paleogeneticist at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences. In a study published Wednesday in the journal Cell, Dr. Fu led a genetic analysis of the dairy products and microbes present in cheese from the Tarim Basin, shedding light on how it was made. Humanity’s love affair with cheese goes back millenniums. Scientists have found fatty residues on 7,000-year-old pottery that were most likely from cheese, and 4,000-year-old Sumerian texts mention the dairy product. But the Tarim Basin samples are the oldest substances in the world that scientists can confidently call cheese. Dr. Fu and her team took samples of cheese scattered about the necks of three mummies from the Tarim Basin. They chemically isolated the fragments of DNA that remained and compared them with the genomes of modern species involved in the cheese-making process. They found traces of cow and goat DNA, indicating that the milk of both animals was used in the ancient cheese. They were also able to track down the DNA of microbes responsible for fermenting the milk into cheese. The researchers found species of bacteria and yeast that, together with milk, coagulate into clumps called kefir grains, which are used to produce fermented, yogurt-like kefir milk and soft, sour kefir cheese. For Dr. Fu, identifying the microbe species that produced the ancient cheese was “really, really exciting,” because cheese-making practices can hint at how people lived and whom they interacted with. The inclusion of the cheese in burials indicates that it was valued, and the multiple milk sources and the kind of bacteria used suggests potential interactions between people in the Tarim Basin, the Xiaohe, and peoples from the Eurasian steppe. “It’s a new way of tracking what human cultures were doing long before or in the absence of language or written accounts,” said Paul Kindstedt, a cheese historian and professor emeritus of food science at the University of Vermont, who was not involved with the new study. At the time the cheese was buried, it was most likely soft and tangy, not unlike modern kefir. To Dr. Fu’s knowledge, no one has tasted the crumbly bits that were pulled out of the tomb. “I think people don’t want to try it because we see that it’s not that attractive,” she said. But if they did taste it, they might have been disappointed. Some archaeologists sampled cheese they found in an Egyptian tomb in the 1930s, and their paper from 1942 noted that it had “no smell and only a dusty taste.” However, Dr. Fu and her colleagues are keen to try to recreate the cheese based upon the information they’ve gleaned about its production. “I think next step, we should make it,” she said.
