42. In canning food by the FRACTIONAL-STERILIZATION CANNING METHOD, the
procedure is much the same as in the one-period cold-pack method. In
fact, the only difference between the two is that blanching and
cold-dipping are omitted, and in their stead the food in the jars is
subjected to three periods of cooking. When the jars of food are made
ready for processing in the sterilizer, they are put in the water bath,
boiled for a short time, and then allowed to cool. After 24 hours, they
are again boiled for the same length of time and allowed to cool. After
another 24 hours, they are subjected to boiling for a third time. Then
the jars of food are removed and sealed as in the one-period cold-pack
method. By the fractional-sterilization method, the spores of bacteria
contained in the food packed in the jars are given a chance to develop
during the 24-hour periods after the first and second cookings, those
which become active being destroyed by cooking the second and third
times. Although some canners prefer this method to those already
mentioned, the majority look on it with disfavor, owing to the length of
time it requires.