"One apple a day keeps the doctor away" Churchill.
But in China it could be "one apple a day call the doctor straight away!".
In China I often find out that many apples are rotten in their center.
Why is that? Is this some side effect of using too many pesticide on apples?
Most Chinese apples are contaminated with pesticide.
The farmers use some plastic bag soaked with pesticide and they surround the apple with it!
As a consequence the pesticide not only contaminate the apple skin, they also penetrate inside the apple.
As always the problem in China is that there is no food chain control. Or if there is, corruption at all level stop it to be effective.
You can check if the apple you buy has too many pesticide.
Examine the skin and scratch it with your fingertip. If the skin is waxy, it has many pesticide.
After you peel the apple, examine the color of the flesh. If the color is too yellow, it might be the effect of the pesticide.