Aging of paddy is a natural phenomenon. Rice is a living organism, with the prolongation of storage time, especially after more than the normal storage period, the internal structure of the rice gradually relaxed, enzyme activity is reduced, respiratory capacity decline, the life force weakened, which is the rice itself physiological, biochemical change process. Even if the rice in storage period is not heat, insects, mold, there is still the natural phenomenon of aging. The aging phenomenon of paddy is manifested in the decline of edible quality and use quality, and when it is seriously aged, the taste is obviously worse and the acidity is obviously increased. The state formulated grain storage quality judgment rules, according to the storage quality of the advantages and disadvantages of the grain will be divided into appropriate storage, should not be stored, stale three categories, used to guide the grain storage enterprises on the stock of grain in due course to push the old storage new. The rules for determining storage quality define stale grain as: rice, corn and wheat whose storage quality has significantly declined, and which are generally not suitable for direct consumption as food rations, excluding finished grains. Whether grain can be used for human consumption or as feed is determined by health standards. The state does not allow the flow of aged grain into the ration market, is to better protect the people's health (health food) point of view to consider, so that the aged grain before reaching the level of inedible, that is, transferred to the manufacture of alcohol, feed and other non-directly edible uses, rather than because of the aged grain is toxic and harmful to the grain.