At present, preserved eggs on the market are duck eggs or preserved eggs, which can be selected according to personal preferences. When buying preserved eggs, you can pay attention to whether there is a quality certification mark. In addition, preserved eggs with high lead and copper content will have more spots on the eggshell surface, and after hulling, you can also see that the protein is dark green or occasionally has black spots, which is not suitable for purchase. Some preserved eggs made by traditional methods will be covered with red soil and straw, which is unsanitary and inconvenient to judge the lead content by appearance, and is not suitable for purchase. It is recommended to buy products with complete packaging and clear labels. Pay attention to the date of production when buying, and pay attention to the way and period of preservation when going home to save. 1. Extreme neurotoxicity: Lead can damage the brain and nerves, making people mentally retarded, unresponsive, hyperactive, inattentive, hearing impaired, learning difficulties and dyskinesia. 2, cause anemia 3, inhibit immunity 4, loss of appetite, unexplained abdominal pain, vomiting, diarrhea or defecation 5, affect the absorption and utilization of minerals and vitamins. Appearance identification leading to (1) calcium deficiency, zinc deficiency and iron deficiency. Observe whether its appearance is complete, damaged or mildewed. You can also feel its elasticity with your hands, or shake an egg to listen to its sound. The surface of a good preserved egg is completely covered with mud, without mildew spots, and the eggshell is intact without damage after peeling off the covering; Elasticity after peeling; There is no bump when shaking. The packaging materials of inferior preserved eggs are damaged or moldy; After peeling off the wrapping material, the eggshell has spots, damage and leakage, and some contents have been polluted; After shaking, there is a sound of water swinging or a feeling of light floating. (2) Identification by optical transmission. After peeling off the package, the preserved eggs were identified according to the light transmission method of fresh eggs, and the color, solidification state and air chamber size of the eggs were observed. The contents of inferior rubber balls are not solidified, but watery, with a large air chamber. (3) Have a taste. The whole preserved egg is solidified, not sticky, clean and elastic, translucent and brown, with loose patterns and textures; When the egg is cut vertically, you can see that the yolk is light brown or light yellow with a thin center. Inferior preserved eggs have a pungent or musty smell. At present, preserved eggs on the market are duck eggs or preserved eggs, which can be selected according to personal preferences. When buying preserved eggs, you can pay attention to whether there is a quality certification mark. In addition, preserved eggs with high lead and copper content will have more spots on the eggshell surface, and after hulling, you can also see that the protein is dark green or occasionally has black spots, which is not suitable for purchase. Some preserved eggs made by traditional methods will be covered with red soil and straw, which is unsanitary and inconvenient to judge the lead content by appearance, and is not suitable for purchase. It is recommended to buy products with complete packaging and clear labels. Pay attention to the date of production when buying, and pay attention to the way and period of preservation when going home to save. Follow-up: Not the answer I want. How can there be light when you buy it? Even in the supermarket, the light is too far away to see. Not to mention tasting, how can I let you taste it if I buy it? She is irreplaceable in my heart. There are preserved eggs on the market on June 20, 2009, including lead-free preserved eggs and lead-free preserved eggs. Consumers should choose lead-free preserved eggs. Because eating preserved eggs containing lead can lead to lead poisoning, which affects hematopoiesis, nerve conduction and cognitive ability, and is prone to dizziness, irritability, inattention, hyperactivity anorexia and mild anemia. How to tell whether preserved eggs contain lead or not? The surface color of the lead ball is dark gray. The surface pollution of eggs is serious and it is difficult to clean. There are many lead spots on the surface, commonly known as gold powder spots; Lead-free rubber ball has smooth surface and few lead spots. The eggshell seems to be oiled and clean. Preserved eggs are generally purchased by the method of "one view, two choices, three shakes and four photos". One view: see if the preserved egg is complete and the color of the eggshell is normal. Generally, damaged eggs, cracked eggs, black-shelled eggs and eggs with severe brown spots belong to inferior eggs and should be removed. Step 2: Put a preserved egg in your hand and gently throw it up two or three times. If you put it back in your hand and feel elastic and heavy, you can judge that it is a high-quality preserved egg, otherwise it is a poor-quality egg. Three shakes: Hold both ends of the preserved egg with your hands, put it in your ear and shake it up, down, left and right a few times to hear that there is no sound of water or impact. If there is a sound of water, break the shell and check it. If both protein and yolk are liquid, they are inferior eggs. Photo 4: If most of the eggs are black or brown and a few are yellow or light red, they are high-quality eggs. If most or all of them are brown transparent body, there are blisters turning back and forth, or one end is crimson, and even there is a cloud-like black solution shaking inside, they are all inferior eggs.