Michigan
State University Extension
Preserving
Food Safely - 01600516
10/13/97
For thousands of years, people have dried many foods to
preserve them for leaner times. Preserving seasonal foods
by drying is still useful and convenient, and it has the
added advantage of conserving storage space.
Successful home food dehydration is dependent on three
basic principles:
Heat: controlled temperature high enough to force out
moisture, but not hot enough to cook the food.
Dry Air: to absorb the released moisture.
Air Circulation: to carry the moisture away.
When food is dehydrated, 80 to 95 percent of the moisture
is removed, inactivating the growth of bacteria and other
spoilage microorganisms, making it a useful method of
preparation.
In hot, dry climates, food will be reduced in a few days
to a moisture level that preserves them. In any climate,
however, you can create satisfactory drying conditions at a
moderate expense by using artificial heat and circulating
air over the food. You can do this:
-- in your own kitchen oven (equipment needed: drying
trays, an oven thermometer and a small fan)
-- in a homemade or commercial portable vegetable dehydrator
(USDA Bulletin 217 has instructions on how to construct
a natural-draft dehydrator. Electric food dehydrator can
be purchased in most appliance stores.