I think the comparison should be between Pasturized Milk (the
ones kept chilled) vs UHT Milk
UHT (Ultra-High Temperature) Milk is milk that has undergone the
UHT process which is partially sterilizing food by heating it for
around 1-2 seconds, at a temperature exceeding 135°C. This
temperature kills the spores in milk. The high temperature also
reduces the processing time, thereby reducing the destruction of
nutrients. UHT milk has a typical shelf life of six to nine months,
until opened. However, they spoil much more rapidly than
pasteurized milk because all the lactobacillus in milk has been
killed by the high temperature heat treatment.
Pasturized Milk undergoes the pasturizing process which involves
the selective removal of a subset of microbes. Pasturized Milk does
not kill the lactobacillus in the milk and it only have a
shelf-life of 2 - 3weeks.
Anyway, the price all comes down to the manufacturing process coz
if a product shelf-life is shorter, they have to increase the price
to cover their losses by dumping the product once it
expires.
