Why can milk that is packaged in small boxes be kept on your pantry shelf without refrigeration?
Answer Because of ultra-high temperature pasteurization
Milk is treated by Ultra High Temperature (UHT) pasteurization (280º for 2 seconds) that kills off the bad (and the good) bacteria. Then it's packaged in sterilized (aseptic) boxes and sealed. This milk will keep for several months on your pantry shelf, but, once opened, it needs to be refrigerated and should be used within a week, just like regular milk. They are generally small boxes to eliminate wasted milk in places where refrigeration is scarce.
Asked by Leni Davenport · Last updated 5 years ago · 113.5K views · SOURCE
