Four Factors Effecting Food Storage

Temperature

has more to do with how long well dried foods store than any other factor. The USDA found seed storage life to double for each 10.08F drop in temperature. Obvious limits exist, but common sense leads one to believe this rule holds true from room temperature down to freezing. The inverse of this rule also holds true with each 10.08F rise in temperature seed storage life is halved. Of course, this applies to other seeds as well.

This chart illustrates constant storage temperature (F) and the corresponding storage life in years. This does not apply to all foods, but is intended to show the relationship temperature has on food storage.

39.76 - - - 40
49.84 - - - 30
59.92 - - - 20
70.00 - - - 10
80.08 - - - 5
90.16 - - - 2.5
100.24 - - 1.25

If you store your food in a warm area, it will only last a fraction of the time if stored in a cool area even if you package food with the very best storage methods. Storing food at 60 degrees F or lower will provide you very good food storage life. An environment of changing temperatures will shorten storage life.

We currently have an average temperature of 80F so we must rotate our stored foods more quickly to avoid spoilage and loss.

Product Moisture

USDA nutritional tables show that dry beans, grains, and flours contain an average of 10% moisture. It is not necessary to remove all moisture but food should be stored as dry as possible. Foods with excess moisture can spoil.

Take care when using dry ice to pack food since ambient moisture condenses and freezes on the outer surface of the dry ice. Long term grain storage should have a moisture content of 10% or less. Food dehydrators are not capable of sufficiently drying foods for long term storage. Foods with 10% moisture levels will crisply snap when bent. Dehydrator foods are leathery and will not store well long term.

Storage Atmosphere

Air contains oxygen which oxidizes foods and promotes bacterial growth which causing food to go rancid. Here are a couple of professional approaches to removing oxygen.

DISPLACE OXYGEN: Purge out all the air with an inert gas. Nitrogen is almost always used because it is very inert. Carbon dioxide is also inert. People often use dry ice - which works pretty well.

ABSORB OXYGEN: Oxygen absorber packets offer a high tech approach. Air contains about 78% nitrogen, 21% oxygen and about 1% other gasses. When the oxygen is absorbed, what remains is about 99% pure nitrogen.

Storage containers need to be strong enough to withstand a slight vacuum when using the oxygen absorber packets. If the container is not air tight the packets will be defeated by incoming oxygen which must be absorbed and in time the storage container will no longer be oxygen free.

Storage Container
Containers need to be air tight.

#10 Cans lined with enamel are air tight and prevent rust from forming.

Sealable food storage buckets - Manufacturer studies show an extremely small amount of air transfer through bucket lids - an amount so small it can be said to be hermetically sealed. Sealable food plastic drums. Be sure containers used are made from food grade material or you will have tainted food.