Source of preserved eggs: According to legend, during the Taichang period of the Ming Dynasty, a small teahouse in Wujiang County, Jiangsu Province, the owner knew how to do business, so the business was booming. Due to the shortage of manpower, the shopkeeper poured the brewed tea into the ashes when entertaining guests. Coincidentally, the shopkeeper also keeps several ducks and loves to lay eggs in the ashes. When the host picks up the egg, it is inevitable that there will be omissions.

Once, the shopkeeper found a lot of duck eggs while cleaning the tea residue from the furnace ash. He thought they were inedible. Who knows, when you peel it off, it's dark and bright with white patterns on it. When you smell it, a special smell comes to your nose. Have a taste, it's fresh, smooth and refreshing. This is the most primitive preserved egg. Later, after continuous exploration and improvement, the production technology of preserved eggs was improved day by day.

Precautions for preserved eggs:

Preserved eggs made by traditional technology have high lead content, because lead oxide is used in the production process, which will play a sealing role and block the small holes on the surface of preserved eggs, thus preventing strong alkali from further reacting with protein. With the progress of technology, after 2008, the state issued a new standard for preserved eggs, which stipulated the lead content.

At present, regular manufacturers have begun to use the "lead-free process" to make preserved eggs, that is, zinc chloride or copper sulfate is used instead of lead oxide, which can reduce the lead content and seal the holes. Judging from the information released by the State Administration of Market Supervision in recent years, there are few cases in which the lead in preserved egg products is over the standard. In short, preserved eggs can be safely eaten as long as they meet the national standards.

Refer to the above content: People's Daily Online-Is preserved eggs safe?