On Food and Cooking

short-time (HTST) method, in which milk is
pumped continuously through a heat
exchanger and held at a minimum of
162ºF/72ºC for 15 seconds. The batch process
has a relatively mild effect on flavor, while
the HTST method is hot enough to denature
around 10% of the whey proteins and generate
the strongly aromatic gas hydrogen sulfide (p.
87). Though this “cooked” flavor was
considered a defect in the early days, U.S.
consumers have come to expect it, and dairies
now often intensify it by pasteurizing at well
above the minimum temperature; 171ºF/77ºC
is commonly used.
The third method of pasteurizing milk is
the ultra-high temperature (UHT) method,
which involves heating milk at 265–300ºF/
130–150ºC either instantaneously or for 1 to 3
seconds, and produces milk that, if packaged
under strictly sterile conditions, can be stored
for months without refrigeration. The longer
UHT treatment imparts a cooked flavor and