If yes, what is the white layer on the surface of plum? Is it harmful to human body?

No problem! ! Generally, there will be some frost on the surface of preserved fruit products, which is said to be sugar.

That white substance is called fruit paste, which contains sugar. Fresh fruit contains a lot of water, glucose and fructose. When it is dried into preserved fruit, the water gradually evaporates, and the glucose and fructose contained in the pulp penetrate into the epidermis. When it penetrates into the skin of preserved fruit, the water evaporates into a layer of white powder.

But it does not rule out that some manufacturers are not good, and choose big manufacturers when eating.