Sterilized milk is dead milk. In boiling all the natural micro-organisms are killed. Boiled milk is more difficult of digestion than raw milk, and should never be given to infants except under the responsibility of a physician. When milk is heated to 212o Fahr., the boiling point of water at sea level, it does not necessarily imply that it is sterile after it has been cooled, unless it has been boiled in bottles stopped with cotton plugs or corks before the boiling.
Milk boiled in an open vessel, allowed to cool in it, and kept in it, is frequently far more dangerous than raw milk.
To sterilize milk put the milk into perfectly clean bottles or jars; if bottles, stop with cotton plugs or clean corks - cotton plugs are preferable; if jars, put on the tops, give a single turn, stand them in a kettle of cold water, cover, bring to boiling point and boil continuously for thirty minutes. Take the kettle from the fire, lift the lid, allow the milk to cool in the water and put it at once in the refrigerator.