Thirteen people were killed in riots in Mozambique last week as the government raised the price of food, water and electricity. Over 400 people were arrested in connection with the riots.

Protests over food also broke out in Egypt recently, bringing back memories of the unrest and riots caused by the food crisis in 2007-2008.

The riots in Mozambique started after the government raised the price of bread by 30 percent, though it lowered it again in response to the riots.

Police opened fire on the thousands of demonstrators as they lit tires, looted food warehouses and did around $3.3 million worth of damage.

Wheat prices have soared by 70 percent on international markets since last year, mainly because of fires and drought in Russia. Usually the world’s third-largest wheat exporter, Russia has banned grain exports until 2011.

Pakistan’s floods are also a factor. Pakistan is usually Asia’s third-largest wheat exporter. However, the recent floods have destroyed over half a million tonnes of Pakistan’s wheat seed stocks.

Yet, much of the price increase is fueled by fears for the future rather than any actually shortfall. 2010 is set to have the third-highest cereal crop harvest on record.

“Most poor countries are still highly vulnerable,” said UN special rapporteur on the right to food Olivier De Schutter. “Their food security is excessively dependent on food imports whose prices are increasingly high and volatile.”

Because there doesn’t appear to be any particular food shortage, the United Nation’s Food and Agriculture Organization (fao) said that it did not believe that there would be a 2008-style food crisis this year. However, the fao is holding a special meeting on the food situation on September 24.

“There is a lot of uncertainty about the evolving supply and demand situation and the measures different countries are taking to limit price variability,” the fao’s statement quoted Hafez Ghanem, one of its top economic officials, as saying.

“Food commodities markets will remain more volatile in the years ahead,” said the fao.

Nations may weather the grain price hikes of this summer without too much difficulty. However, the Mozambique protests show just how quickly high food prices can spark deadly riots. As the fao said, food prices are “volatile,” meaning they could easily spike more in the future.