Milk is a near perfect medium for bacteria growth. Any contamination from handling, transport, etc. can lead to BIG trouble. Pasteurization not only adds to product safety but greatly extends shelf life.

A commercial milk pasteurizer is a 4 section plate style heat exchanger for constant flow processing. The first set of plates alternate cold milk in next to hot milk out. This section is pre heat & pre cool. The second section alternates milk being cooked next to hot water. For home pasteurizing, use a double boiler to keep from scorching the milk. Monitor the temp. with a thermometer, 160* F for 20 minutes or 161* F for 20 seconds is all the hotter you need to go (go to 165* F for a safety margin).

The homogenization process in the packaging of milk probably alters taste more than the pasteurization. It keeps the cream from readily separating and adds to the eye appeal of finished product.