Actually, the saying is that a few bad apples spoils the bunch, which refers to the tendency of decay or infestation to quickly spread throughout the bushel: http://www.npr.org/2011/05/09/136017612/bad-apple-proverbs-t... ("But as the memory of rotting apples fades, the meaning of the 'bad apple' proverb has changed. In 19th century America, it was a staple of Sunday morning sermons: 'As one bad apple spoils the others, so you must show no quarter to sin or sinners.' Or it could suggest that finding one malefactor in a group should make you suspicious of everybody else. 'A bad apple spoils the bin,' one journalist wrote in 1898 of the Dreyfus Affair; if one officer is capable of forgery then why wouldn't others be as well? Back then, nobody ever talked about 'just a few bad apples' or 'only a few rotten apples' — the whole point was that even one was enough to taint the group."). In this case, the saying, the real one, is apropos. It might just be a few bad apples, but they taint the whole culture.