Milk is boiled at 60 degree Celsius for half an hour and suddenly its cooled, by this method milk is pasteurization and preserved for long period.  Then they are packed and marketed, when the milk is boiled the micro organisms in them get killed so that they could not get spoiled by the room temperature. When the milk is pasteurized they could be ready to use that they milk could be boiled for the use. But sometimes they are boiled in very high temperature so that they could not need any boiling they could be used readily by the people. The milk is very important in the people life they need milk in their breakfast so that they could get the calcium from that. It is a nature source of the calcium; the children should be given the milk in their daily routine so that they stay healthy. When they don’t take milk they could lack calcium in them and they could eat other foods source that has the calcium content. The pasteurization is the method that is followed all over the world to preserve the milk and give them to the people. All the milk companies produce their milk in this way.