Although I am personally disturbed by the absence of discussion regarding the reliability of the government's standards itself, too, putting it aside, for Mr. Frid clarified that it was beyond the scope of this paper in his comment, I would like to raise two questions.
One is regarding the Figure 4 in the paper. This reminds me the article issued in Mainichi Shinbun last December. As in this article, Codex standards as well as EU standards appear "high", because they are based on the assumption that 10% of all foods are contaminated, while Japanese standards, both the old and the new, is based on the assumption that 50% of all foods are contaminated.
EU standards (EURATOM No. 3954/87) is the regulation for imported food following a nuclear emergency, and this standards was applied to foods imported from Japan by Commission Implementing Regulation No.297/2011 on March 25th, 2011. The numbers shown in Fig.4 are those in 3954/87, which is the standards for imported foods from the region which had a nuclear emergency, as it was applied to foods from Japan after Fukushima by 297/2011.
Given the difference of assumed proportion of contaminated food to the total consumption, I think that the comparison presented in Fig.4 is not valid, or at least is misleading for it gives an impression as if Japanese standards is considerably strict among other international standards.
Moreover, 297/2011 was amended a month later by Commission Implementing Regulation No. 351/2011, namely, the standards for foods imported from Japan was amended to ensure consistency with levels applied in Japan. Thus the Caesium standards got tightened, respectively, foods for infants (400 --> 200), Milk and dairy products (1000 --> 200), Other foodstuffs (1250 --> 500), despite that the assumed proportion to the total consumption is much smaller than that in Japan.
My second question is regarding "ND" which Mr. Frid talked about in his comment. Mr. Frid says "ND" means "you can safely eat", but "ND" should not be confound with the safeness of food. Because a) "ND" depends on the detection limit of each test method, and b) thus it does not mean "0" existence of radionuclide, and according to the linear no-threshold model (though there are contesting models, given that scientists have not yet reached to the definite conclusion, the validity of LNT model should not be disregarded), radiation is harmful for human body no matter how small its dose is.
Data released by Ministry of Health, Labour and Welfare (MHLW) are obtained through tests carried by each municipality. On September 29th, 2011 MHLW notified to municipalities that thereafter those cases whose radionuclide level was less than the detection limit should be reported as "< actual number of detection limit", instead of "ND". This change of policy took a little time but gradually got prevailed, and the term "ND" can no longer be found as of November test results (issued in December).
Thanks to this policy change, we can now know the detection limit of each test, which varies from less than 1 bq/kg to as high as 50 bq/kg at a glance. This is one of reasons why Citizen's Radioactivity Measuring Stations are spreading throughout the country. Besides that the official testing is very limited sample measuring, the minimum level detected in official tests can be different 50 times as much between municipalities and employed methods. This is not clearly a kind of benchmark for people to determine the safeness of given food.