There are two separate items you have to understand.
1. The value of the US Dollar $ effects the cost of anythung manufactured abroad or has parts or ingredents manufactured abroad. I suspect that this is the reason that stock prices are climbing even as the shares traded are stable.
2. When the US Government competes with the US Consumer the price of the items become more expensive as they become more scarce and thus the price goes up.
When you have the government buying grains, and other products to send to Haiti and South America it makes food made from them cost more for the American people who buy it.
It will soon get worse as more and more people go on food stamps and welfare. Then when the Federal Government can no longer pay Welfare and the recipients begin to riot and steal it from the stores the stores will stop putting it out. Then the price will go balistic.
Remember! While Spam taste like crap it is much more nutricious as a food source. Stock up on things that come in cans that you can put in a plastic wrap, then in a wood box and bury it deep in your garden. When the riots get bad the Government will start shopping at "YOUR HOUSE" instead of Walmart. It is still a Federal Offence to stockpile more food than your family can consume in a 15 day period.
Prepare, but prepare inteligently, and remember that loose lips sink ships!