The cause is the same as why tortilla prices have sparked riots in Mexico, and why milk is up 10% so far this year in the U.S. while beef, pork and chicken prices are up over 20% - and the rise is just begining.
The cause: the stupidest programs politicians have ever imagined, never mind implemented, conversion of prime grade food production into SUV fuel. Worldwide, farmland is being converted from soybeans, wheat, vegetables and other food crops to corn to feed the food-to-fuel program.
Instant noodles are going up at least 20% as well, because the cost of the palm oil they are made with has doubled. Much of it is now being diverted for use as biodiesel.
Legislation is very much needed to outlaw conversion of primary food resources to motor fuel. In the U.S. the majority component of landfills is wood products and paper which could be digested into alcohol. We have a vast pollution problem from agricultural wastes which could be digested into fuel. Instead we're digesting primary food stocks into alcohol.
Of course this legislation will never happen. The major beneficiaries of the corn-to-fuel program are the giant grain cartels like ADM and Cargill who have tremendous economic clout in both state and national legislatures.
And they've convinced an unthinking public in love with their Hummers that this is a good thing.