In Western culture, the milk is first heated to about 80 °C (176 °F) to kill any undesirable bacteria[citation needed] and to denature the milk proteins so that they set together rather than form curds. In some places, such as parts of India & Bangladesh curds are a desired component and milk is not pasteurized but boiled. The milk is then cooled to about 45 °C (112 °F).[citation needed] The bacterial culture is added, and the temperature of 45 °C is maintained for 4 to 7 hours to allow fermentation.