Young Blonde Girl With Apples

Fallen apples
Eating fallen apples (known in the UK as 'windfalls'), rather than picking directly from the tree, is generally safe. There may be a risk of food poisoning if the orchard is also the area of keeping cattle or other animals, which may contaminate the apples with feces. Still, the risk may be significantly higher if the apples are used to make home-made (unpasteurized) cider or juice, thus letting E. coli multiply.
On the other hand, if the apples are eaten unprocessed, and kept free from risk of contamination with animal feces, then eating fallen apples is generally safe, even if there is some general decay or worms in them. Still, they may be submerged in water with salt added, which kills the worms. Apparent molds may be largely removed by putting in water with some vinegar added, but if they are of a large quantity, then there might be mold or mold products left to evoke mold health issues such as allergic reactions and respiratory problems.