Yogurt

Yogurt or yoghurt ( /ˈjoʊɡərt/ or /ˈjɒɡərt/; other spellings listed below) is a dairy product produced by bacterial fermentation of milk. The bacteria used to make yogurt are known as "yogurt cultures". Fermentation of lactose by these bacteria produces lactic acid, which acts on milk protein to give yogurt its texture and its characteristic tang.

Worldwide, cow's milk is most commonly used to make yogurt, but milk from water buffalo, goats, ewes, mares, camels, and yaks is also used in various parts of the world.

Dairy yogurt is produced using a culture of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus bacteria. In addition, other lactobacilli and bifidobacteria are also sometimes added during or after culturing yogurt.

By food law, some countries require a certain amount of colony forming units of microorganisms to allow sour milk be named as "yogurt", e.g., Swiss Food Law: Article 56 yogurt 2 The final product must contain a total of at least 10 million colony forming units of microorganisms under paragraph 1 or 1.2 per gram.

The milk is first heated to about 80 °C (176 °F) to kill any undesirable bacteria and to denature the milk proteins so that they set together rather than form curds. The milk is then cooled to about 45 °C (112 °F). The bacteria culture is added, and the temperature is maintained for 4 to 7 hours to allow fermentation.