The ban on shipping rice from a district in the city of Fukushima due to high levels of radioactive cesium shows the need to amend the two-phase test currently performed to check the grain for radiation, farm minister Michihiko Kano indicated Friday.
The contaminated rice was not tested by the government, which only examines samples. The high level of cesium was detected only when a farmer took it to a local agriclutural cooperative to be tested on Monday.
“The shipment ban is an unfortunate result. We will need to review the radioactive contamination test system for next year,” he said, adding that details will be discussed with the health ministry and Fukushima Prefecture.
The ban was instituted Thursday after radioactive cesium was detected in rice harvested at a farm in the Onami district exceeding the government’s provisional limit. The unmilled rice registered 630 becquerels of radioactive cesium per kilogram, while the provisional limit is 500 becquerels.
The result came as a shock because none of the rice samples from six other farms in Onami exceeded the limit in previous tests. The farm ministry has been paying special attention to rice, a staple of the Japanese diet, and the tests are considered elaborate.
But “it is a sampling test, so if you ask whether the test guarantees 100 percent safety (for all rice), it is hard to deny the possibility of a loophole,” farm ministry official Yukihiro Umeshita said.
Asked if he may change the way tests are carried out and whether the ministry will check all rice, Kano did not give a specific answer and only said the current regimen needs a rethink.
The Onami district, located at the base of a mountainous area in Fukushima, has had relatively high radiation levels.
Kano said that rice harvested in areas with similar geographical characteristics may need detailed testing.
The government set the guideline for the two-phase test to check rice in August.
The first phase checks rice before harvesting in municipalities whose farm soil has registered 1,000 becquerels per kilogram or whose air radiation level is 0.1 microsievert per hour.
The preliminary test sets the standard at 200 becquerels.
If the rice exceeds that level, the area where it was grown gets checked more thoroughly in the second phase, which is the main test held after harvesting the rice.
Rice that passes the first phase is checked again with seven samples from each municipality.
According to the farm ministry, 1,276 samples were tested as of Thursday, and only one exceeded the limit.
Information from Kyodo added