Tokyo Food Safety Information Center » Tokyo Metropolitan Government food safety FAQ »What kind of tests are carried out on radioactive substances in food and what kind of results do they produce?

What kind of tests are carried out on radioactive substances in food and what kind of results do they produce?

What does the measurement result “Not Detected” mean?
Is it possible to check the place of production and processing for food?
Was testing for radioactive substances in food conducted before the nuclear power station accident in Fukushima Prefecture?

Each prefecture tests the food produced in the prefecture for radioactive substances in food. The national government indicates the approach for the frequency of testing and the target items based on test results to date, and food that potentially contains a lot of radioactive substances and commonly eaten foods are prioritized for testing.
Since April 2012, approximately one million food items have been tested nationwide, and about 0.4%, or 4,034 of them exceeded the limit values (as of March 31, 2016). You can check the latest test results and information on shipment restrictions and so on the website of the Ministry of Health, Labour and Welfare and each local government.

Testing for radioactive substances in food is mainly conducted by local governments which have shipment restrictions in the past and neighboring local governments. In addition to vegetables and fruit, food that is subject to testing includes items in which a lot of radioactive cesium has been detected such as mushrooms, including shiitake and bracken, edible wild plants, and rice, food that is highly impacted by feeding methods such as milk and beet, and marine products.
Even the Tokyo Metropolitan Government inspects agriculture, forestry and fishery products produced in the metropolitan area once a week based on the approach indicated by the national government. In addition to this, food distributed within the metropolitan area, primarily food that residents eat often and foods such as milk that are consumed by children, as well as beef slaughtered at the Tokyo Metropolitan Central Wholesale Market are also inspected. There test results are published on the website.

Bureau of Industrial and Labor Affairs Tokyo Metropolitan Government: Radioactive Material Findings for Agricultural, Forestry, and Fishery Products Produced in Tokyo

Bureau of Public Welfare and Public Health Tokyo Metropolitan Government: Levels of radioactive contaminants in marketed food in Tokyo

Bureau of Public Welfare and Public Health Tokyo Metropolitan Government: Levels of radioactive contaminants in beef slaughtered at Tokyo Metropolitan Central Wholesale Market

Some of the municipalities within the Tokyo Metropolitan Area carry out testing. Please check the website of each municipality.

The Ministry of Health, Labour and Welfare compiles the nationwide test results and publishes them on its website by area of production. You can check the place of production and processing for food on its packaging, on store displays, or on the manufacturer’s website. Some industry groups also publish test results.
The equipment used for testing is mainly a sodium iodide (NaI) scintillation spectrometer in simple inspections for testing in a relatively short period of time, and germanium (Ge) semiconductor detector in detailed testing.
When “Not Detected (＜10)” is stated in the test results, it indicates that a reliable test result with the equipment used can be obtained for 10 Becquerel/kg or more and that the radioactive substances contained in the measured food were less than 10 Becquerel/kg. Sometimes it is described as “ND (an acronym for Not Detected)” or “＜10” which mean the same as “Not Detected.” The minimum measurable value (detection limit) varies depending on the testing equipment, the testing period, the food to be tested, and the amount of radioactive substances contained.
Testing for radioactive substances in Japanese-produced agricultural, livestock and fishery products and processed foods was carried out even before the accident. Historical test results are posted on the website of the Secretariat of the Nuclear Regulation Authority.