The international community has no excuse for the food crisis and the riots that come with it, a top United Nations official declared on Friday. The new UN's expert on the right to food says that this is the price for 20 years of mistakes, AFP informs, quoting an interview Oliver de Shutter offered to Le Monde.

"We are paying for 20 years of mistakes. Nothing was done to prevent speculation on raw materials, though it was predictable investors would turn to these markets following the stockmarket slowdown.

"This is a call to order. The days of cheap food are behind us," said the UN's new expert on the right to food, arguing that the crisis showed the "limits of industrial agriculture."

Schutter said the World Bank and International Monetary Fund (IMF) had "gravely underestimated the need to invest in agriculture," and accused the IMF of forcing indebted developing countries to invest in export cash crops at the expense of food self-sufficiency.

Billions of dollars have been poured into transforming corn, soy beans and sugar to ethanol and biodiesel to help wean rich economies from their addiction to fossil fuels, mainly in the United States, Brazil, Canada and Europe.

"The ambitious goals for biofuel production set by the United States and the European Union are irresponsible," Schutter charged, calling for a freeze on investments in the sector.

But he also distanced himself from the hardline stance of his Swiss predecessor in the UN post Jean Ziegler, who had called for an outright moratorium on biofuels, describing them as a "crime against humanity."

Schutter said he believed a coordinated international response would manage to avert famine between now and the autumn harvests.

UN Secretary General Ban Ki-moon earlier this week set up a new global task force to address the food crisis, saying the first priority must be to "feed the hungry".

The World Food Program is appealing to donors for an extra $755 million (€487 million) to enable it to purchase enough food to meet its global commitments.

Workers across Asia, where one billion people are now seriously affected by the food price surge, made food their May Day battle cry, with volatile crowds staging rallies in the Philippines, Indonesia, Singapore and Bangkok.