Besides the wax itself, what residue concern is potentially sealed in by the post-harvest coating?

Pesticides or fungicides applied during cultivation

While the edible waxes themselves are approved as safe for consumption, a significant public concern centers on the potential for these coatings to trap undesirable substances that were present on the apple before the waxing process began. Specifically, if the initial washing phase conducted by the packer is insufficient, residues from pesticides or fungicides used during the apple's cultivation phase can become sealed beneath the applied wax layer. This trapped residue presents a risk because it is less likely to be removed by simple rinsing or scrubbing afterward. Regulatory agencies do monitor pesticide levels to ensure treated produce remains safe, but the mechanism of the wax sealing in these contaminants is the core of this particular safety discussion.