As Japan grows more of the rice it consumes, authorities are urged to be more stringent in keeping radioactive cesium out of the food supply.

Following news reports last week about radioactive iodine leaking outside the earthquake-crippled Daiichi nuclear power plant in Fukushima, officials have begun testing harvested rice for possible contamination since Saturday.

In the rice paddies of Nihonmatsu City, more than 56 kilometers away from the power plant, rice crops tested positive for radioactive cesium, prefecture officials said in a report in The New York Times.

After the March 11 earthquake and tsunami catastrophes, the Japanese officials amended their regulations dubbing food commodities with as much as 500 becquerels per kilogram of radioactive substance as safe for consumption, the Times said.

The rice crops tested in Nihonmatsu reached the benchmark for radioactive cesium. In the previous tests, the rice crops in more than 400 locations in Fukushima Prefecture contained only 150 becquerels per kilogram of cesium, a stark contrast to the current radiation level.

Government officials also conducted tests on rice crops in other areas for possible contamination of radioactive substance saying they will ban shipment if the same levels of radioactive cesium are found on rice.

Japanese are furious over the latest results, criticizing government officials for neglecting their duties. Children and pregnant women are more vulnerable, even from moderate radiation levels.

Earlier, Japan banned shipment and recalled massive food products such as milk, tea and spinach and livestock meat like beef for contamination of radioactive substance in alarming levels. The rice contamination this time inflicts a major blow to all Japanese as they rely on rice as the staple oftheir diet.

The government officials promised to be keener in checking food safety.