Every wednesday from 9:00 till 13:00 and every saturday from 9:00 till 17:00 there is a streetmarket around the "Grote Kerk". There are no bins here, but it works if you ask the vendors at the end of the day.
There's a company called Fruit Company @ the street Stadsbrink, with a Albert Heijn on the oppposite side, if you drop by here at the end of the day you can ask for the leftovers.
There's a company called Paul & Martie's @ the street Stationsstraat, on the left side of the public library. If you go here in the afternoon around 2-3, you can ask them if you can have the left-overs and then you can pick them up around 5-6.
At Bennekom, a village nearby, there's a Plus @ the street Dorpsstraat. At the back, there are bins, where you sometimes can find amazing stuff. It closes at 9PM but people will be working there until 10PM. After closing the bin is sometimes closed but otherwise openable with a general triangle key. Mind the employees, they are very much against people taking stuff from the dumpster.