TOKYO — Considering the immensity of the earthquake and tsunami that hit Japan on March 11, the country’s basic food processing industry sustained little damage. The exception, of course, centered in the northeast section of the country where the damage from the twin natural disasters, along with severe damage to a nuclear power plant, have either shut down or severely interrupted operations at several plants in an area of Japan that is not heavily populated.

Most of the nation’s food industry is located to serve the Tokyo Bay area as well as the southern part of the nation where population is heaviest.

Operating difficulties in areas not directly affected by the earthquake and severe flooding were primarily the result of periodic power interruptions. Due to the breakdown at the Fukushima Daiichi nuclear power plant, electrical supplies were being rationed through rolling blackout. This was the practice of the Tokyo Electric Power Co., where blackouts of three to four hours per day were conducted in different areas served. At the same time, major factories such as the largest flour mills had their own power supplies and were not affected by the blackouts.

In turn, the rolling blackout disrupted transportation in a country that heavily counts on rail services to move people. Commuting problems have been severe in many areas, but the major food companies assert that they have had little or no production interruptions because employees could not reach plants.

In view of the widespread media attention focused on the nuclear plant problems, the Food and Agriculture Organization of the United Nations issued a report saying that “there is no evidence of food safety risks because of imports from Japan.” The F.A.O. added that “food safety concerns are restricted to food from the affected zone around the Fukushima Daiichi nuclear power plant.” It added, “Given the reported safety measures, it would be unlikely that food production or harvesting is taking place in the evacuated area.”