Price of transporting food to market and to run farms etc, would be my first guess. Whatever it is, my monthly grocery budget has had to double!
It is definitely the price of fuel and as I said wait till the minimum wage kicks in. The only thing which will keep processed food from going up too high is competition on foreign markets.
IOW, tainted food from China, a lot of people don't care if it is possibly tainted or canned in a substandard plant as long as it is cheap.