If you sell a certain type item, and the shop is set as a pawn shop to buy, it will buy that type item. So you would have to make it sell food and crops and buy food and crops. There is a way to keep it from stocking what it buys, but there is no way to differentiate food gotten at a festival, or food bought, etc. So it is not feasible to allow them to sell strawberries, potatos, carrots, etc.

Now, if a player thinks that's a great idea, you can always buy a shop that deals in fruits and vegetables.

Baily