The first post-war convoy of UN aid reached Baghdad on Sunday.
The 50-truck convoy, chartered by the World Food Programme from Jordanian firms and carrying 1,400 tonnes of wheat flour, drove into a warehouse guarded by American troops. The journey had taken four days.
Officials said the flour would be distributed early next month, when food is expected to become increasingly scarce.
"The arrival of the convoy might allow the opening of a well-functioning food aid corridor that opens a major lifeline into Iraq, bringing food that would replenish the stock that WFP assumes could be running out as soon as early May," WFP spokesman Maarten Roest said in Jordan.
"Until now there have been no reports of immediate shortages of foodstuffs," Roest said. "We expect food supplies might start to run out by end of this month and plan to have enough food stocks ready for distribution by the beginning of May."
US military officials said the trucks would be unloaded by Monday after soldiers cleared broken glass and damaged machinery out of the warehouse, which had been targeted by looters in the days following Saddam Hussein's overthrow on April 9.
"We have a lot of army vehicles there clearing stuff out," Lieutenant Brian Johnson said.
Two US Bradley fighting vehicles and an Abrams tank were inside the compound, their guns pointed out to the street.
Saddam's government maintained state storage facilities for food, which was rationed as a result of UN economic sanctions imposed on Iraq following its invasion of Kuwait in 1990.
Convoy leader Adnan Dugum said the trucks had been held up for two days at Ramadi, 90 km west of Baghdad, because no suitable warehouse was available in the capital.
WFP officials in Jordan said earlier there were unconfirmed reports shots had been fired at the convoy during its journey. But Dugum said the trucks had not run into any problems.