Assessment of the effectiveness of the post-Fukushima food monitoring campaign in the first year after the nuclear accident: A hypothesis.

The purpose of this study was to assess whether or not the food monitoring campaign after the Fukushima nuclear accident has been successful in reducing the number of above-limit-food from reaching the consumers. The hypothesis of this study is that the fraction of "post-market" food can be used for this purpose, when the post-market fraction in the above-limit (p') items is compared to the post-market fraction in the entity of food items (p) that have been screened for radionuclides ((134)Cs and (137)Cs). Indeed the post-market fraction in most vegetarian produce decreased significantly in the above-limit food items (p'/p < 1), indicating a high efficiency of the monitoring campaign. For tea, however, the analysis reveals a low efficiency of the campaign (p'/p ≈ 1). For beef, the fraction of post-market-foods within the above-limit samples was much higher than the respective fraction in the entity of measured samples (p'/p > 1), indicating a much lower effectiveness of the monitoring action for beef. The author speculates that, by following the governmental monitoring manual (which gives "meat" only second priority), the sudden exceedances caught the monitoring agencies unprepared and triggered a much higher density monitoring of beef with the delay of several weeks. Even then, many above limit items reached the market (mainly because the monitoring during this period had focused on the post-market). Therefore, it is likely that some above-limit beef has been consumed by the public. For other meat products, the fraction of post-market samples was very low, which does not allow for the validation of the effectiveness of the monitoring campaign. Overall, the monitoring seemed to have been more effective for vegetarian produce than for meat.