Inspired by Trade-peror, Shyrramar, Aussielurker and Garbarsardar

This has been mentioned by the original refrigeration/supermarket ideas and Trade-peror’s threads.
It’s based on the food/gold pooling idea, but tried to apply it in the current game mechanics.

To implement this idea, the different food bonuses have to be increased.

The supermarket (refrigeration) improvement could function like the Wall st. small wonder does.
Each city containing the improvement gets a 10% bonus on either food collected or food stored.

Second ability:
The improvement also allows this city to trade food with other cities and/or rivals.
Each 1 food would cost 1, 2 or 3 gold from the city income of the food receiving city.
This would be enabled by right clicking the improvement or the domestic advisor screen.
When trading with rivals it would function as any other trade but would in addition to regular food, include specific foods that vary in price, like exotic fruits, maize, potatoes, sugar, spice, shellfish or rice.
These prices would be determined by distance and availability.

Or:
Granaries enable trade at high cost, and refrigeration and supermarket lower the cost for each food.
(reminiscent of economics and wealth)

I think this is a viable idea, though it could also upset the game balance.

Most actual economies involve one area where food is produced and another where commerce/industry is focused. A famous example is that Rome was basically fed by Egyptian wheat. It'd be nice if the game could simulate this.

-- The Hypnotoad