Preserved eggs evolved from salted duck eggs recorded in Qi Yaomin in the Northern Wei Dynasty. Zhu Yushan's miscellaneous department has a clear record of preserved eggs, which was written in Xiaozong 1504 in Ming Dynasty. The inventor of preserved eggs is no longer exam-proof.

There are many legends about the invention of preserved eggs. The earliest written record is Zhu Yushan's house miscellaneous department in the seventeenth year of Emperor Xiaozong of Ming Dynasty: "Chaos Zi: Take a bucket of charcoal ash, add one liter of lime, add salt water, put it in a pot, warm it, put it on eggs, and mix the yellow and white evenly on May 7." This "chaos" is the embryonic form of preserved eggs.

Matters needing attention in selecting preserved eggs

It should be noted that the preserved eggs made by traditional technology have high lead content, because lead oxide is used as the main component in the production process to ensure that the preserved eggs will not liquefy again after maturity and keep their color and taste delicious for a long time.

According to the information released by the State Administration of Market Supervision in recent years, the lead in preserved egg products sampled rarely exceeds the standard. Therefore, as long as it is preserved eggs that meet the national standards, it can be safely eaten.

To buy preserved eggs, we should choose products with complete packaging, gray surface, few black spots and no cracks through formal channels. Preserved eggs should be kept in a cool and ventilated place with low temperature, and peeled preserved eggs should be eaten within two hours. If the preserved egg's protein is light green and has an odor, it means that it has gone bad and cannot be eaten.