Long-Term Monitoring of Radioactive Cesium in Commercial Foods and Dietary Intake Estimated by Total Diet Studies in Japan after the Fukushima Daiichi Nuclear Power Plant Accident.

Following the Fukushima Daiichi Nuclear Power Plant accident in 2011, Japan implemented extensive monitoring of radioactive materials in foods and established strict regulatory limits based on an annual effective dose of 1 mSv/year from artificial radionuclides. This review summarizes long-term surveillance data on radioactive cesium (r-Cs) in commercial foods and long-term assessments of dietary intake of r-Cs and strontium-90 (90Sr) using the total diet study (TDS)/market basket (MB) method. Monitoring of commercial foods demonstrated that pre-shipment inspections and production controls are highly effective for cultivated agricultural products and livestock products, with regulatory exceedances occurring almost exclusively in wild mushrooms, wild edible plants, and wildlife-derived foods. No r-Cs has been detected in any infant food sample since monitoring began. TDS-based assessments show that the committed effective dose from r-Cs declined rapidly during the first few years after the accident and has remained at a very low level (generally below 0.001 mSv/year) nationwide since around 2017, while 90Sr levels exhibited no clear regional differences and remained comparable to pre-accident background levels. These findings confirm that Japan's long-term food safety controls have kept internal radiation exposure far below international safety limits. The integration of surveillance, TDS monitoring, and risk management provides a robust evidence-based model for ensuring food safety following nuclear events.