(2) technique. When buying eggs, hold the eggs with your thumb, forefinger and middle finger and shake them. Fresh eggs are silent, and bad people will send out Tik Tok when shaking hands. The louder the voice, the worse. (3) irradiation method. Hold the egg gently with your hand and observe the light. Good egg protein is clear and translucent, with a small empty room at one end, while bad eggs are darker in color and larger in empty room. Some eggs are stained, which is a sign of obsolescence or deterioration (4) floating method. Take 500 grams of water, add 500 grams of salt, dissolve, and put the eggs in the water. The eggs that sink horizontally at the bottom are fresh eggs, but the big head floats slightly above and the small head floats slightly below. An egg left on the water for too long is a bad guy. Hehe, this kind of egg is rotten. Looking at the light, the fresh egg is clear and transparent, the boundary between egg white and yolk is clear, the bear is small and orange-red, and there are no black spots and red shadows in the egg; Stale eggs, egg whites are yellow or black spots, yellow is unclear, and bad people have large black blocks. Put the eggs in a basin full of cold water. If the egg is under the water, it is fresh. If the egg leans in the water, it means that the egg has been stored for three to five days. If an egg stands upright in the water, it is old. If it floats on the water, it is likely to have deteriorated. Put the eggs on the ground and turn them gently with your hands. Fresh eggs stop after two or three weeks, while bad eggs last for a long time. A stale egg won't get faster or slower. Take the egg in your hand and shake it gently. If there is no noise, it is a good egg. If there is noise, this is a yellow or almost spoiled egg.