ROME, October 30 -- With the world's urban populations growing by more than 60 million people a year, supplying and distributing food to cities is becoming an increasingly pressing challenge, according to the UN Food and Agriculture Organization (FAO).

FAO said in a report the situation is particularly serious in developing countries where post-harvest storage, processing and marketing facilities have failed to keep pace with accelerating urbanization.

"The population of urban areas worldwide is growing by 3.4 percent per annum and by about 5 percent in sub-Saharan Africa. By the year 2000 there will be around 200 cities with populations of over one million and 21 "megacities" with populations of over 10 million people," FAO said. "Worldwide, cities and towns are currently absorbing over 60 million people each year."

"This growth will continue to present enormous challenges for the suppliers and distributors of food," the report said. Guaranteeing the efficient distribution of low-cost and nutritious food to the urban poor , it said, "will be one of the major food security issues of the coming decades."

The report, "Food for Consumers: Marketing, Processing and Distribution," is one of a series of technical background documents prepared for the World Food Summit to be held at FAO headquarters 13-17 November.

Heads of state and government from close to 200 countries have been invited to the Summit to renew their commitment to achieving universal food security and agree on a Plan of Action to be carried out in cooperation with international and non-governmental organizations, the private sector and civil society.

The technical document noted that distribution systems in developed countries are becoming increasingly concentrated in hypermarkets and supermarkets, which purchase directly from the producer or processor, bypassing traditional distribution systems.

As "extreme examples," it cited Belgium, France and the United Kingdom where only 10 percent of retail units account for more than 80 percent of food distribution.

Over time, the same is likely to happen in both developing countries and the former centrally planned economies of Central and Eastern Europe, the report said.

But it said that in many countries street food venders still play "important social and economic roles." Street vending serves as a source of employment and income, particularly for women, and contributes "a significant share to the daily food consumption of a large number of people," the report said.

"The assumption has been made that, with modernization, this informal sector would disappear," it noted. "This has not been the case as street food vending has become a global urban phenomenon," providing nutritious foods at low prices to many people.

However, basic food hygiene and safety problems need attention, the report said.

Street vendors would be better utilized, FAO said, if they were educated in hygienic practices, provided with tap water and garbage disposal facilities and involved in decisions about sites for their stands or carts.

FAO said that improving the handling of food between farm and consumer at all phases can do much to improve the access of the poor to safe and inexpensive food in both urban and rural areas.

"Reducing post-harvest losses can lead to significant reductions in consumer prices," it added. "Such efficiency improvements are vital if those with limited purchasing power are to be able to afford sufficient food of adequate quality

"In many rural areas employment in post-production activities such as processing can make a major contribution to increasing incomes and thus alleviating problems of undernutrition. Women play an important role, frequently a dominant one, in such activities."