Should the US impose limits on food exports?

http://www.foxnews.com/politics/2011/03/07/economists-urge-obama-overreact-high-food-prices/

According to the article: "Leading advocates for the world’s poorest and hungriest are urging President Obama not to “overreact” to recent spikes in food prices, particularly by imposing export bans on U.S. agricultural products."  It will be interesting to see if things get to the point where loud voices start calling for limits on food exports if shortages start to become noticeable here in the US.  That could create quite a food crisis worldwide if it were to transpire...