Yogurt is a dairy product created through the bacterial fermentation of milk, commonly using Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus bacteria. The fermentation process involves converting sugars in the milk into lactic acid, giving yogurt its texture and tangy taste. Various types of milk, including cow’s milk, water buffalo, goats, ewes, mares, camels, and yaks, can be used to make yogurt, and different milk characteristics yield distinct results. Additional lactobacilli and bifidobacteria may be incorporated during or after the fermentation process. The production typically involves maintaining a warm temperature for 4 to 12 hours, with temperatures between 30–45 °C, to facilitate fermentation, balancing speed and texture considerations.
Discovered around 5000 BC, yogurt’s beginnings are linked to Neolithic people in Central Asia and Mesopotamia with its fermentation process probably stumbled upon by chance. Ancient Greece had a similar dairy product called oxygala, while Pliny the Elder mentioned yogurt-like substances in certain “barbarous nations.” Medieval Turks recorded the use of yogurt, likely fermented in goat skin bags. The Mughal Indian emperor Akbar’s cooks flavoured yogurt with mustard seeds and cinnamon, and its healing properties were noted in European encounters. Until the 1900s, yogurt was a dietary staple in various regions globally.