Are any of those items grown and processed in Toronto? How did they get there and why are they cheaper than rural? Just logistics? How does adding a couple hundred km to a mango from 10,00km awa justify a 100% increase?
Well, they can be shipped here by rail, air or truck whichever is the cheapest. And if they are being imported, they are probably coming first here anyways. So whatever shipping cost to Toronto is in whatever price (unless it goes through Vancouver). The said bananas probably come here, some get sent to local Toronto stores by truck (cheaper than by air). Others get sent outward to distribution. All costs will be recovered by the people delivering. Perhaps the cost of having a depot in Toronto is divided over the 500 shipments in a given week so it doesn't add up. But take the cost of the depot for one flight / week, and your costs are higher.
This is not subsidies, just logistics. If they distribution point for Canada was in Nunavut, the opposite would likely be true but it does not make economic sense for this model to happen.