2 BULLETIN 1265, U. S. DEPARTMENT OF AGRICULTURE 
It was Appert (£), 2 the man who laid the foundation of modern 
canning methods, who first practiced scalding in the preparation of 
certain vegetables for bottling. Asparagus, artichokes, cauliflower, 
spinach, and chicory were given this preliminary treatment, the 
object being, as expressed in connection with his discussion on as- 
paragus, " to remove the acridity peculiar to this vegetable." That 
undesirable substances which have been variously described are elimi- 
nated from certain vegetables by scalding has been generally recog- 
nized, and because of this, in part, the practice has been widely 
recommended. The effect of this treatment upon the coloring sub- 
stances in the various types of materials has received a great deal 
of attention also. By many, it has been held that the scalding " starts 
the flow of coloring matter," " intensifies the color," or " brings the 
coloring matter to the surface," which, it is thought, makes possible 
a better colored and more attractive product. Others, however, have 
held that neither the color nor flavor is improved. 
That scalding assists in cleansing the material is of course well 
known, and many writers have asserted the removal of " mucous," 
" mucilaginous," " gummy," and " viscid " substances from the sur- 
face of various fresh raw foods. Shrinkage or reduction in bulk of 
vegetables and fruits as a result of scalding has been widely noted, 
and attention has been called to the softening of the tissues and the 
increase in flexibility of such substances, as string beans, etc. (1) 
which facilitates packing into containers. 
Scalding has been found of great value in the peeling of tomatoes 
and certain other fruits. It has been asserted also that it is of value 
as an aid to sterilization, and further, that this treatment results in 
a clearer liquor in the canned product. Other reasons advanced in 
favor of scalding are, that it makes possible the elimination of the 
usual " exhaust," that it makes the texture of the canned food firmer, 
that scalded vegetables cook more rapidly in the can, and that it 
assists also in the grading of such products as peas, etc. 
With a great many writers, chilling the freshly scalded materials 
by immersion in cold water, popularly known as the " cold dip," is 
considered a necessary corollary to the scalding treatment, and 
several benefits claimed to follow the practice of chilling have been 
noted. Nearly all have recognized the fact that the materials are 
more easily and comfortably handled as a result of being cooled, 
and that the pulp of certain fruits, such as tomatoes and peaches, 
is made firmer, and may thus be more conveniently and economically 
packed. It appears to be a more or less common notion that in some 
way the coloring matter in the various fruits and vegetables is 
" coagulated " or " set " as a result of chilling, so that in the steriliza- 
tion process which follows the natural coloring substances are not 
destroyed. 
Of particular interest are the statements regarding the value of 
the combined scalding and chilling operations as aids to sterilization. 
These, while expressed in different ways, may be summarized by the 
following quotation from one of these publications: "The change 
from hot to cold, and vice versa, produces the double shock necessary 
to successful destruction of spore-producing bacteria." 
'Serial cumbers (italic) in parentheses refer to "Literature citod *' at the end of this 
bulletin, 
