Are biofuels to blame for rising food prices worldwide?

It's no secret that food prices are rising drastically, and for the foreseeable future, worldwide.  According to CNN,

However, consumers still face at least 10 years of more expensive food, according to preliminary FAO projections.

Among the driving forces are petroleum prices, which increase the cost of everything from fertilizers to transport to food processing. Rising demand for meat and dairy in rapidly developing countries such as China and India is sending up the cost of grain, used for cattle feed, as is the demand for raw materials to make biofuels.

What's rare is that the spikes are hitting all major foods in most countries at once. Food prices rose 4 percent in the U.S. last year, the highest rise since 1990, and are expected to climb as much again this year, according to the U.S. Department of Agriculture.

As of December, 37 countries faced food crises, and 20 had imposed some sort of food-price controls.

Affluent Silicon Valley consumers probably don't feel the pinch, and probably never will, because they spend such a tiny fraction of their income on food.  But for the world's poor, food is usually their second largest expense, after shelter, and a 10% increase in food prices could well push them from subsistence to starvation. 

The Christian Science Monitor examines the role of biofuel crops in raising food prices.  Predictably, the biofuels industry, supported by farm-state driven legislation and buoyed by subsidies, has produced studies that minimize their impact on commodity prices.  Says the Monitor,

In a counterpoint study last month by corn growers and the biofuels industry, higher corn prices were found to be only a small element in rising food costs overall – although higher energy costs for fuel to transport crops and grow them were a larger factor.

There is still much doubt about the sustainability of biofuels, i.e. whether they are a net positive in terms of energy production vs. consumption, and in terms of carbon emissions.  With so much uncertainty about the cost-benefit ratio of biofuels, and the very real need for more arable land for food crops, shouldn't policy makers and land stewards be focusing on increasing food production and not artificially subsidizing biofuel production?