The Carry-One Ferry with Incompatible Cargo

A trader must ferry three items — a fox, a goose, and a sack of beans — across a river in a small boat that can carry the trader plus at most one item per trip. If left together unattended, the fox eats the goose, and the goose eats the beans (the fox ignores the beans). The trader rows every trip. What is the minimum number of one-way crossings needed to get all three items safely to the far bank?