Dry milk products are probably the most sensitive to environmental conditions storage foods there are, particularly to temperature and moisture content. Their vitamins A and D are also photosensitive and will break down rapidly if exposed to light.
The area where your dry milk is stored should be kept as cool as possible. If it is possible to do so, air-conditioning or even refrigeration can greatly extend the nutrient shelf life.
If the storage container is transparent or translucent then it should be put into a second container opaque to light or stored in a dark room.
Dry milk will absorb moisture and odors from the air so storage containers should be impervious to both air and moisture. The drier it can be kept, the better it will keep. The use of desiccants is an excellent idea. Oxygen also speeds decomposition. Powdered milk canned with nitrogen or carbon dioxide to replace air (which contains oxygen) will keep longer than powdered milk exposed to air. Vacuum canning or oxygen absorbers will also decrease the available oxygen.
If the dry milk purchased was not packaged for long term storage then it should be repackaged right away.
I purchase the instant variety at my local grocery and repack it when I get it home. I've seen a number of methods used for this and any of them should work.
The method I now use is to pour the powder into clean, dry half-gallon canning jars. Once the jars are filled I add a small desiccant pack and seal. They are dated and stored in the ubiquitous cool, dark place. They must be guarded against breakage, but they offer the advantage of not holding odors, thus allowing for reuse after suitable cleaning. Since they are as transparent the contents must be protected against light. Vacuum sealing and then storing in a dark place may be the best method. Larger jars of 1 gallon size could be used and then re-vacuum sealed after each use. An O2 absorber would take care of any remaining oxygen and would, itself, last longer when used in conjunction with the vacuum sealer. Being glass, the jar can be reused as well as the lid and ring if they're properly cleaned.
Clean, sound plastic one and two liter soda bottles can also be used, but probably should be used just once since the plastic is somewhat permeable and will hold odors.
If you have access to a can sealer, #10 cans make wonderful storage containers for dry milk, particularly if used in conjunction with O2 absorbers.
Another method I've seen used is to remove the paper envelopes of milk powder from the cardboard box they come from the grocery store in and to put them in dated plastic bags. These bags are not sealed. The unsealed bags are then placed in a larger, air tight, opaque container. I've heard of plastic buckets, fifty cal and 20 mm ammo cans being used for this purpose. A healthy quantity of desiccant was also placed in the container. This would be another area where O2 absorption packets should serve well. It's important to remember the containers should be clean and odor-free.
Please see Section IV Specific Equipment Questions for information concerning the proper use of containers, desiccants, compressed gasses, dry ice and oxygen absorbers.
B.2.1 SHELF LIFE OF DRY MILKS
From: SacoFoods@aol.com (Amy Thompson)
To: Dunross@dkeep.com (Alan Hagan)
Subject: SACO Mix'nDrink Instant Pure Skim Milk
May 9, 1996
Dear Mr. Hagan:
Thank you for your e-mail today and for your interest in SACO Mix'nDrink Pure Skim Milk.
Our Mix'n Drink will keep its nutrition value for up to about two years if kept cool and dry, and the only vitamins that actually decrease over time are the vitamins A and D. These are not shelf-stable vitamins and are sensitive to heat and light. A good rule of thumb to follow is that the vitamins A and D will dissipate at a rate of about 20% every year if stored properly. The less heat and moisture the milk is exposed to, the better the vitamins will keep. A freezer could extend the shelf life, as long as the powder does not get moisture in it. If you had to put a time limit on the Mix'nDrink, for rotation purposes, I would date it at two years after the date of purchase.
After opening a package of dry milk, transfer the powder to a tightly covered glass or metal container (dry milk can pick up odors from plastic containers) and keep it in the refrigerator. Unsealed nonfat dry milk keeps for a few months; dry whole milk for a few weeks.
From: SacoFoods@aol.com (Amy Thompson)
To: Dunross@dkeep.com (Alan Hagan)
Subject: SACO Mix'nDrink Instant Pure Skim Milk
May 21, 1996
Dear Mr. Hagan:
Since vitamins A and D are heat and light sensitive, I would say that your 1 1/2 year shelf life is very reasonable. If you are trying to determine when the nutritional value has been affected more than 40%, as you previously indicated, you should be pretty safe with that time element, as long as it is not exposed to extreme heat.
[Eds note: We were discussing the higher average temperatures found in Florida and other hot climates and the effect that it would have on their dry milk's nutrient content]
Misc.Survivalism FAQs maintained by Alan T. Hagan, athagan@sprintmail.com
Copyright ©1996, 1997, 1998, 1999. Alan T. Hagan. All rights reserved.
Excluding contributions attributed to specific individuals all material in this work is copyrighted to Alan T. Hagan and all rights are reserved. This work may be copied and distributed freely as long as the entire text, my and the contributor's names and this copyright notice remain intact, unless my prior express permission has been obtained. This FAQ may not be distributed for financial gain, included in commercial collections or compilations or included as a part of the content of any web site without prior, express permission from the author.