Make sure that you only buy organic Apples:

 Picture-perfect apples are usually a result of synthetic dye, and/or coatings of inedible wax in order to prevent rotting.

However since yellow apples don't sell as much as the red ones, many of them get painted.

Apples are known to be one of the most sprayed fruits out there and can give you an allergic reaction from all the herbicides and pesticides.

 If you love apples, especially those red ones, make sure that you only buy organic.