Food should be open to free market because everything else is. If you make a change to food then you are leaving it open to argue that anything can be changed. This would open a door that we do not want to open in our society, so food needs to be left to free market.
Government interference in the food market deters future investors and stifles competition, the ultimate result of which is higher prices across the board for consumers. The price for food should be set by the simple rules of supply and demand, which would lower the cost of essential food and nutritional items for the country.