Over time the plastic bags will deteriorate - they get sticky.

Yes - for long term storage you should use mylar bags and 02 absorbers.

I thought milk powder had a short storage life? What kind of powdered milk stores long term? Thanks.

Powdered Milk is one of those items that has a pretty short "Best Before" or "Expiry" date, but many people store it successfully for far longer lengths of time.
As with all food stores, over time the nutritional value, and general quality of the food decreases, but not does not make it inedible.
Powdered milk is very sensitive to sunlight and temperature changes, so proper storage is important.
A method to increase the safe storage time is to put into mylar bags with O2 absorbers, and place it in your freezer until you are ready to use it.
I use this method as I do not generally go through very much powdered milk, only in baking really, and it remains good after 2 years.

http://extension.usu.edu/foodstorage/htm/dried-milk

This link has suggestions on safe storage, and suggest that some powdered milk can be safely stored for 3-5 years, but only for non-fat dried milk.

The non-fat dry milk I that is advertised on the LDS flyers for sale in cans is good for 20 years - with proper storage I always assume we can get the same results. 🙂

I leave everything in the store package so it doesn't get contaminated and then put them in rubbermaid containers in my basement, maybe I need to rethink this???

Hi NewWoman - welcome 🙂 Yes please - rethink your storage!! The idea is to eliminate oxygen, heat, moisture and bugs. Many product you buy in the store are already contaminated with weevils which don't come to light until later in the form of pantry moths. With grains your best bet is to freeze the items for three days, let come to room temperature and repackage in mylar with O2 absorbers. Powdered milk definitely needs to be packaged correctly or it will certainly go bad/off/smelly/taste weird. Many foods however are good LONG past their "expiry date". Pasta, many grains, dried beans etc may have some minor nutritional deficiencies but are still good to eat YEARS past the date. Good packaging will ensure the best results however!

Hey Anita, Thanks for the tips. I guess thats my next step; going through what I have and tossing or sealing properly. Thank goodness I haven't yet managed to store away pounds and pounds of stuff or this could be disheartening 🙂

Hey Anita, Thanks for the welcome & the tips. I guess thats my next step; going through what I have and tossing or sealing properly. Thank goodness I haven't yet managed to store away pounds and pounds of stuff or this could be disheartening 🙂