Looking for Dried Foods and Spoilage: How to Determine if Your Dried Foods have Spoiled, and How to Prevent Spoilage of Dehydrated Fruits and Vegetables in 2021? Scroll down this page and follow the links. And if you bring home some fruit or vegetables and want to can, freeze, make jam, salsa or pickles, see this page for simple, reliable, illustrated canning, freezing or preserving directions. There are plenty of other related resources, click on the resources dropdown above.
It can be tough to accurately determine whether
any food has
gone bad without a lab test, since many pathogens (botulism, as an example)
leave no visible signs, and are colorless, odorless, tasteless, etc..
Generally, we rely on following the approved preparation and
canning/freezing/drying process rigorously to ensure safety is built in.
But dried foods can be even more difficult. Mostly it depends upon how carefully the foods were prepared and dried (cleanliness and attaining the optimal moisture content for the produce), and then how they were stored. Dried foods kept in the freezer can last years.
Assuming you don't have access to a food science laboratory:
Dried foods are susceptible to insect contamination and
moisture reabsorption and must be properly packaged and stored immediately.
First, cool completely. Warm food causes sweating which could provide enough
moisture for mold to grow. Pack foods into clean, dry insect-proof
containers as tightly as possible without crushing.
Containers: Store dried foods in clean, dry home canning jars, plastic freezer containers with tight-fitting lids or in plastic freezer bags. Vacuum packaging is also a good option. Pack foods in amounts that can be used all at once. Each time a package is re-opened, the food is exposed to air and moisture that can lower the quality of the food and result in spoilage.
Quantities: Pack food in amounts that will be used in a recipe. Every time a package is re-opened, the food is exposed to air and moisture that lower the quality of the food.
Sulphuring: Fruit that has been sulfured should not touch metal. Place the fruit in a plastic bag before storing it in a metal can. Sulfur fumes will react with the metal and cause color changes in the fruit.
Light and Heat: Dried foods should be stored in cool, dry, dark areas.
Time in storage: Recommended storage times for dried foods
range from 4 months to 1 year. Because food quality is affected by heat, the
storage temperature helps determine the length of storage; the higher the
temperature, the shorter the storage time. Most dried fruits can be stored
for 1 year at 60ºF, 6 months at 80ºF. Vegetables have about half the
shelf-life of fruits. Dried foods kept in a good deep freezer can last
Check for moisture: Foods that are packaged seemingly "bone dry" can spoil if moisture is reabsorbed during storage. Check dried foods frequently during storage to see if they are still dry. Glass containers are excellent for storage because any moisture that collects on the inside can be seen easily. Foods affected by moisture, but not spoiled, should be used immediately or redried and repackaged. Moldy foods should be discarded.
The moisture content of home dried fruit
should be about 20 percent. When the fruit is taken from the dehydrator, the
remaining moisture may not be distributed equally among the pieces because
of their size or their location in the dehydrator. Conditioning is the
process used to equalize the moisture. It reduces the risk of mold growth.
To condition the fruit, take the dried fruit that has cooled and pack it loosely in plastic or glass jars. Seal the containers and let them stand for 7 to 10 days. The excess moisture in some pieces will be absorbed by the drier pieces. Shake the jars daily to separate the pieces and check the moisture condensation. If condensation develops in the jar, return the fruit to the dehydrator for more drying. After conditioning, package and store the fruit as described above.
Vegetables should be dried until they are brittle or "crisp." Some vegetables actually shatter if hit with a hammer. At this stage, they should contain about 10 percent moisture. Because they are so dry, they do not need conditioning like fruits.
Dried food is sometimes
contaminated by insects or molds, which can cause spoilage. Sulfuring fruit
usually prevents this type of contamination. After meat and vegetables have
been dried, they can be pasteurized to make them safe. It is especially
important to pasteurize food dried outdoors, where it was probably
To pasteurize, heat the oven to 175 degrees F. (80 C.). Set the pieces of dried food in a single layer on a tray or cookie sheet. Heat in the oven with the door closed for 15 minutes. Remove from the oven and allow the food to cool before packaging. Alternatively, the dried food can be pasteurized by freezing it for 1 to 2 weeks and then storing it.
Here's the food dehydrator I use!:
The Presto Pressure
canners are out
of stock, but Tfal's
Above is the
2020 version of
the Ball Blue Book