Preserved egg duck rolls can be eaten right after opening the bag.

The lead content of preserved eggs produced by traditional techniques is high because lead oxide is used in the production process. This substance has a sealing effect and can block the small holes on the surface of preserved eggs. , thereby preventing the strong base from further chemical reaction with the protein. With the advancement of technology, after 2008, the country introduced new standards for preserved eggs, stipulating the lead content in them.

Nowadays, regular manufacturers have begun to use "lead-free technology" to make preserved eggs, that is, using zinc chloride or copper sulfate instead of lead oxide, which can not only reduce the lead content, but also seal the holes. hole function. According to information released by the State Administration for Market Regulation in recent years, the preserved egg products sampled rarely exceed the standard for lead. In short, as long as the preserved eggs meet national standards, they can be eaten with confidence.

Purchase preserved eggs through formal channels and choose products with complete packaging, gray surface, few black spots, and no cracks. The preserved eggs should be placed in a cool, ventilated place with a low temperature, and should not be stored for more than one month. It is best to eat the peeled preserved eggs within two hours. If the egg whites are light green and smell foul, it means they have gone bad and cannot be eaten.