the not knowing where food comes from seems surprisingly common. My secretary's husband is a gardener. He was taking care of a garden which included a vegetable patch, and noticed that the home owner's never seemed to harvest any pf the veg. So, he thought maybe they weren't sure about which things were in season/ripe, and offered to harvest a selection each time he was there, and leave them a box. They still didn't use any of the veg. He asked whether there was a problem, and the homeowner told him that she didn't want to eat any of it because it was all dirty . . . Apparently this lady could not be brought to believe that washing things such as carrots might be an option, of that the ones she bought at waitrose might have touched earth at some point before turning up clean and shiny in the supermarket..
He ended up turning the vegetable patch into flowerbeds.