Martin Fackler

ONAMI, JAPAN: In the fall, as this valleys rice paddies ripened into a carpet of gold, inspectors came to check for radioactive contamination.

Onami sits just 35 miles northwest of the wrecked Fukushima Dai-ichi nuclear plant, which spewed radioactive cesium over much of this rural region last March. However, the government inspectors declared Onamis rice safe for consumption after testing just two of its 154 rice farms.

Then, a few days later, a skeptical farmer in Onami, who wanted to be sure his rice was safe for a visiting grandson, had his crop tested, only to find it contained levels of cesium that exceeded the governments safety limit. In the weeks that followed, more than a dozen other farmers also found unsafe levels of cesium. The panic that followed forced the Japanese government to intervene, with promises to test more than 25,000 rice farms in eastern Fukushima prefecture, where the plant is located.

The uproar underscores how, almost a year after a huge earthquake and tsunami caused meltdowns at the Fukushima Dai-ichi plant, Japan still struggles to protect its food supply from radioactive contamination. The discovery of tainted rice in Onami and a similar case in July involving beef have left officials scrambling to plug gaps in food-screening measures, many of which were introduced after the accident.

The repeated failures have done more than raise concerns that some Japanese may have been exposed to unsafe levels of radiation in their food, as regrettable as that is. They have also had a corrosive effect on public confidence in the food-monitoring efforts, with a growing segment of the public and even many experts coming to believe that officials have understated or even covered up the true extent of the public health risk in order to limit both the economic damage and the size of potential compensation payments.

Critics say farm and health officials have been too quick to allow food to go to market without adequate testing, or have ignored calls from consumers to fully disclose test results. And they say the government can no longer pull the wool over the publics eyes, as they contend it has done routinely in the past.

Since the accident, the government has tried to continue its business-as-usual approach of understating the severity of the accident and insisting that it knows best, said Mitsuhiro Fukao, an economics professor at Keio University in Tokyo who has written about the loss of trust in government. But the people are learning from the blogs, Twitter and Facebook that the governments food-monitoring system is simply not credible.

One result has been a burst of civic activism, rare in a nation whose civil society that depends on its elite bureaucrats more than citizen groups to safeguard the national interests, including public health. No longer confident that government is looking out for their interests, newly formed groups of consumers and even farmers are beginning their own radiation-monitoring efforts.