Wild mushrooms / 337 food items exceed levels under new radiation safety standards

Wild mushrooms from Akita Prefecture on display at a grocery store in Aomori city (Mutsumi Mitobe)

Wild mushrooms far from Fukushima show high levels of cesium 
Asahi Shimbun November 21, 2012
Wild mushrooms, a seasonal delicacy in many parts of Japan, have lost their magic.


Wild mushrooms, a seasonal delicacy in many parts of Japan, have lost their magic.

Tourism industry officials and restaurant operators have been aghast to learn that wild mushrooms picked far from the site of the nuclear disaster in Fukushima Prefecture last year are showing high levels of radioactive cesium.

Last year, only wild mushrooms picked in Fukushima Prefecture were found to have cesium levels that exceeded legal standards.

This year, however, wild mushrooms from as far away as Aomori, Nagano and Shizuoka prefectures, all more than 200 kilometers from Fukushima, have been found to be contaminated with cesium.

The central government has asked 17 prefectural governments in eastern Japan to test wild mushrooms for cesium.

The task is difficult because differentiating types of wild mushroom is not easy. For this reason, it was decided that if even a single mushroom type had more than the legally allowed level of cesium in at least two municipalities in a prefecture, a blanket ban will be imposed on shipments from those municipalities.

Another problem is that decontamination work in mountainous areas is extremely difficult. Because of this, there has yet to be a single case in which a ban has been lifted.

For example, “chichitake” mushrooms picked in Towada, Aomori Prefecture, in October were found to have cesium levels of 120 becquerels per kilogram. Towada is located 350 kilometers north of the Fukushima No. 1 plant.

Under the Food Sanitation Law, the legal standard for cesium is 100 becquerels per kilogram.

The central government issued a shipment restriction and the Aomori prefectural government banned the sale of all wild mushrooms picked in the city, including “nameko” and “kuritake,” or brick cap, mushrooms.

A 42-year-old man who works in Towada’s tourism industry fretted about the consequences of the ban.

“We are unable to offer mushrooms in tempura or potted stew form that 80 percent of our customers order,” he said. “It is taking a heavy toll on business.”

He said there are many repeat visitors who crave the opportunity to eat wild mushrooms.

“I also don’t want to explain why we can’t provide the mushrooms because that could lead to negative publicity that radiation is also a major concern in Aomori,” he said.

A variety of mushroom called “sakura shimeji” picked in Aomori city was also found to be slightly in excess of legal standards in October. All fungi picked in Aomori city disappeared from store shelves after the prefectural government issued instructions to halt shipments.

The operator of a grocery store near JR Aomori Station who is also a mushroom researcher decided to stop handling all wild mushrooms regardless of origin.

“Even if I am told the mushrooms were picked outside of Aomori city, I still cannot take responsibility,” said Yutaka Tezuka, 61. “I truly regret not being able to offer this autumn delicacy.”

Hoto is a popular dish in Yamanashi Prefecture that combines flat udon noodles with vegetables in stew form.

However, Tenkajaya, a hoto restaurant in the town of Fujikawaguchiko, has removed hoto stew with wild mushrooms from its menu.

The dish matches the autumn tourism season, leading the 70-year-old restaurant owner to say, “While it hurts our business, I am also saddened when I see disappointed tourists who cannot order the dish.”

According to the Ministry of Health, Labor and Welfare, Fukushima Prefecture was the only region that was slapped with a shipment restriction for wild mushrooms last year.

One reason for the increase in such restrictions this year is a lowering of the legal standard for cesium from 500 becquerels per kilogram to 100 becquerels.

As of Nov. 16, officials said 93 municipalities in 10 prefectures, including Fukushima, had a shipment restriction in place.

For five prefectures–Aomori, Saitama, Yamanashi, Nagano and Shizuoka–wild mushrooms constitute the only produce for which a shipment ban is in effect.

Cesium levels have also risen in various areas compared with last year.

According to tests requested by the central government, the highest levels recorded this year were 120 becquerels in Aomori Prefecture, up from only 60 becquerels last year; 2,100 becquerels in Nagano Prefecture (1,320 becquerels last year); and 3,000 becquerels in Tochigi Prefecture (134 becquerels last year).

Yasuyuki Muramatsu, a chemistry professor at Gakushuin University who specializes in radiation effects on ecology, said, “While the detailed mechanism is still unclear, mushrooms can more easily absorb cesium in comparison to plants because they are fungi.”

As for why cesium levels are higher this autumn, Muramatsu said, “There is the possibility that radioactive materials that were attached to the trunks and leaves of trees last year were washed away by the rain and entered the soil into which mushrooms extend their fungal filament.”

Muramatsu cautioned that some types of wild mushroom may have high cesium levels next year as well, which will require continued testing.



337 food items exceed levels under new radiation safety standards
May 02, 2012
Everyday ingredients were among 337 foodstuffs found to have radiation levels exceeding new safety standards set by the health ministry in April.

The products, including “shiitake” mushrooms grown on tree logs, bamboo shoots and seafood, were detected in nine prefectures.

The ministry had anticipated that the foodstuffs would not pass.

The new standard for radioactive cesium, implemented April 1, is 100 becquerels per kilogram for food in general, compared with the interim standard of 500 becquerels until March.

Food items with more than 100 becquerels per kilogram cannot be shipped to markets.

The interim standard will continue to apply to processed food made by the end of March as well as beef, rice and soybeans.

Of the 13,867 food products inspected in April, 350 items exceeded the interim and new standards.

Of those, 55 items exceeded 500 becquerels per kilogram. Most of them would not subject to control under the interim standard.

Among the nine prefectures, Fukushima, site of the crippled Fukushima No. 1 nuclear power plant, had the largest number of food items exceeding the government’s safety standard at 142, followed by Tochigi, 69; Ibaraki, 50; Miyagi, 36; Iwate, 35; Chiba, 13; Yamagata and Gunma, 2 each; and Kanagawa, 1.

Of the food items, bamboo shoots, shiitake grown on tree logs, “kogomi” (wild fern plant) and “fukinoto” (wild butterbur buds) showed high levels of radiation, partly due to their shipment time.

As for seafood, sea bass caught in Sendai Bay as well as sea bass and flatfish caught in waters off Ibaraki Prefecture were suspended from shipment.

The new allowable limits are 50 becquerels per kilogram of milk and baby food and 10 becquerels per kilogram for drinking water. But no sample exceeded the limit.

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