You can buy all the food from farmers and set any price, no more expensive than a private market ...
But this project requires the total capital of several players.
up to 36 -37, one player can probably raise the price, having a government of democracy ...
Farmers, seeing how you inflate the price, will seek to sell at the highest price, depriving you of the speculative interest. It's hard for me to imagine if it will be beneficial.