Old rice, which has been used for more than five years, has a poor taste and almost no nutrition. According to experiments, old rice is prone to produce aflatoxin, which is a carcinogen and does great harm to human body.

High-quality millet grain size, uniform color, milky white, yellow or golden yellow, shiny, less broken rice, no moth, no impurities. Put a small amount of millet to be tested on soft white paper, breathe through your mouth to make it moist, and then rub the millet with the paper several times to see if there is a slight yellow on the paper. If there is yellow, it means that the millet to be tested is dyed with yellow pigment. In addition, a small amount of samples can also be soaked in water to observe the color change of water. If there is a slight yellow color, it means that yellow pigment is mixed.

High-quality millet smells fresh and has no other peculiar smell. The severely deteriorated millet is easy to be pulverized by hand twisting, and there are many broken rice, which smells slightly musty, sour, rotten or other abnormal smells.

High-quality millet tastes delicious, slightly sweet and has no peculiar smell. Inferior millet tastes tasteless, slightly bitter and astringent.

Fresh whole grains are the most vigorous and nutritious. So when we eat, we must try to eat fresh millet. Compared with fresh grain, the nutritional content of those old rotten millet has been greatly reduced. Studies have shown that fresh millet porridge has protective effect on gastric mucosa and is suitable for patients with chronic gastritis and gastric ulcer, while old millet stored for a long time has ulcer effect.

Old soybeans also produce aflatoxin, which is harmful to human body.