This process does not involve actual freezing, but implies
preservation in chambers at a temperature maintained a few degrees
above freezing point. This method does not affect the flavor or
nutritive value of food so much as freezing.

SEALING.

Sealing is accomplished not only in the process of canning but by
covering with substances which are impermeable. Beef has been
preserved for considerable time by immersing in hot fat in which it
was allowed to remain after cooling.

CHEMICALS.

Chemicals are sometimes used in the preservation of food, but the
other methods are safer.




CHAPTER V.

Foods Containing Protein, or Nitrogenous Matter.


Animal foods contain nutritive matter in a concentrated form, and
being chemically similar to the composition of the body is doubtless
the reason why they assimilate more readily than vegetable foods,
although the latter are richer in mineral matter. The most valuable
animal foods in common use are meat, eggs, milk, fish, gelatin and