The apple symbolizes original sin, which has spread to all men
Romans 5:18
Therefore as by the offence of one judgment came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification of life.
A similar concept is found in Joshua, where the sin of Achan affects the whole nation:
Joshua 22:20
Did not Achan the son of Zerah commit a trespass in the accursed thing, and wrath fell on all the congregation of Israel? and that man perished not alone in his iniquity.