I'm not a scientist, but the more I read, the more concerned I get about BPA, a chemical used in the plastic linings of 'tin' cans, and a host of other food and water containers. It seems that this chemical is now believed to cause significant and harmful hormonal changes in humans.

I think it is wise to have some long term storage of basic food, especially of beans and grains. I am now in the process of phasing out canned beans in favor of dry beans. The latest research seems to indicate that dry beans retain significant nutritional value for up to 30 years if stored properly.

Here is some info:

http://www.usdrybeans.com/wp-content/uploads/2010/11/BeanBriefs-Fall-2010.pdf

Also:

www.providentliving.org