The public panic over the threat of radioactive food has subsided in the four years since the Fukushima No. 1 nuclear power plant experienced three reactor core meltdowns and spewed massive amounts of fallout, but worries persist.

Seikatsu Club, a mail-order food delivery co-op, maintains an online database that includes more than 700,000 results of radiation tests on food items. Page views have fallen to about one-tenth of their peak in 2012, said Hiroshi Tsuchida, a quality management division chief with the co-op, but there are people who still visit the site almost daily.

"For such members, we are continuing testing and disclosing all the data on our website," Tsuchida told The Japan Times. "In Ukraine, there are screening devices at markets where people check food even today, nearly 30 years since the (start of the Chernobyl) nuclear disaster. I believe we should do the same."