Concentration of Radioactive Cesium in Domestic Foods Collected from the Japanese Market in Fiscal Years 2014–2016

Abstract

Between fiscal years 2014 and 2016, we surveyed the concentration of radioactive cesium in commercial foods produced in areas where there is a risk of radiation contamination due to the Fukushima Daiichi nuclear disaster. The number of samples with a concentration of radioactive cesium that exceeded the regulatory limit 100 Bq/kg for general foods was 9 out of 1,516 0.6 in fiscal 2014, 12 out of 900 1.3 in fiscal 2015, and 10 out of 654 1.5 in fiscal 2016. Even though some samples were expected to be contaminated with radioactive cesium, because wild mushrooms and edible wild plants were intentionally included in this survey, the percentage of samples that exceeded the regulatory limit was only around 1 . The surveillance results confirmed that the pre-shipment food monitoring conducted by local governments was properly and efficiently performed, although continuous monitoring of the concentration of radioactive cesium in cultivated and wild mushrooms, edible wild plants, and wild animal meats is still required.

Radiocesium Concentration in Commercially-Available Foods Produced in Japan: 2017-2019

“…Although detection rates in this study were higher than rates previously reported in the fiscal 2012-2015 surveys (2.7-5.2%) 7,8) , this does not necessarily indicate that radioactive contamination has spread, as this study focused on selected foods (mushrooms and edible wild plants) and areas considered to be with high probability of r-Cs detection. According to results of a nationwide inspection of radioactive materials in foods published on the MHLW website, the detection rate of r-Cs in all commercially-available foods was 0.54% in fiscal 2017 17) , 0.49% in fiscal 2018 18) , and 0.42% in fiscal 2019 19) .…”

“…In contrast, the numbers of samples surveyed for aquatic products and others were only 3 items. This was because that the probability of exceeding the standard limit for these categories were low based on previous surveys 2,7,8) . The proportion of each food category in the total samples inspected did not change substantially.…”

“…The survey was conducted in 17 prefectures in Japan (Aomori, Iwate, Akita, Miyagi, Yamagata, Fukushima, Ibaraki, Tochigi, Gunma, Chiba, Saitama, Tokyo, Kanagawa, Niigata, Yamanashi, Nagano, and Shizuoka prefectures) designated as target local governments in the “Concepts of Inspection Planning and the Establishment and Cancellation of Items and Areas to which Restriction on Distribution and/or Consumption of Foods concerned Applies” in March 24, 2017 10 ) , March 23, 2018 11 ) , and March 22, 2019 12 ) . Based on the survey results of up to fiscal 2016 2 , 7 , 8 ) , we focused on areas where the probability of r-Cs detection was considered to be high.…”

“…We surveyed all foods classified as general foods and originating from the survey areas, including fresh foods and processed foods. Based on the trends of r-Cs concentrations found in previous reports 2 , 7 , 8 ) , we decided to focus on edible wild plants and wild mushroom as they’re difficult to control cultivation/feeding, and log- cultivated mushrooms. We also surveyed items that are controllable of cultivation/feeding to see if the inspection plans formulated by local governments were complied.…”

“…These results confirmed that both the effectiveness of pre-shipment inspections based on the lowered standard limit and of the shipping restrictions. Between fiscal 2014 and 2016, we surveyed the purchased products mainly consisting of known food items and areas with high probability of r-Cs detection 8 ) . The percentage of samples that exceeded the standard limit was about 1% in that survey, although those food itemss were selectd from those with high r-Cs detection probability, such as wild mushrooms, log-cultivated mushrooms, and edible wild plants harvested in the Tohoku and Northern Kanto areas.…”