1. You can't eat flour when it's expired. The shelf life is usually determined by the factory according to the best eating time of flour. If the shelf life is exceeded, not only the nutritional value and taste will be reduced, but also the flour will be prone to mildew and insects, producing toxic and harmful substances, which will be harmful to the body after eating.

2. If the flour is stored for a long time, its color, character and smell may change, such as mildew, caking and peculiar smell. Although some harmful substances can be reduced by high temperature treatment, they cannot be completely eliminated. Deteriorated flour is easy to breed toxic bacteria such as Aspergillus flavus, Mucor and Aspergillus oryzae. Even after cooking, it can cause poisoning symptoms, such as headache, nausea, vomiting, abdominal pain, diarrhea and cyanosis. Aflatoxin produced by Aspergillus may also cause liver injury, which is serious and even life-threatening.

3. It is recommended to pay attention to food hygiene every day. Most foods cannot be eaten after the shelf life. In addition, the storage environment of flour also has certain influence on the storage time. If the flour is left in a hot and humid environment for a long time, it is more likely to deteriorate, worm or even mold, and the shelf life may be shortened.