For years I have been under the misconception that cornmeal could not be stored for long periods of time. I always believed that it would turn the oils rancid. As a result, I have always stored popcorn or dent corn in whole kernels. In this form, it stores well, but not all grinders will handle whole grain corn. Some like the Country Living Grain Mill will, but many of the lower-priced ones will not handle it.
I recently came across some information form BYU (Brigham Young University) in Utah. Because of being LDS they do a lot of research on the storage life of various foods. A recent study that they conducted involved the storage of corn meal. Number 10 cans of corn meal with low oxygen content from 1-33 years old were studied. The results indicated that it was acceptable for use.
The study available at https://scholarsarchive.byu.edu/facpub/29/ stated “There was no significant decrease over storage time in aroma, texture, flavor, and overall acceptability in corn meal, cornbread or corn meal cereal.” It lost color becoming significantly less yellow and red during storage.
Based on this study I feel that storing in number 10 cans or Mylar bags with oxygen absorber is quite acceptable.