TAKAMATSU–The pesticide dichlorvos, which had contaminated gyoza dumplings imported from China, was detected in sliced frozen mackerel processed in an area of China that handles a large volume of farm produce.

The fish was sold in Japan by Kouzai Bussan Co., based in Sanuki city, east of here, company officials said.

They said 0.14 parts per million (ppm) of the organophosphorus pesticide was found in the product called Aburi Toro Shimesaba Suraisu, a package of 20 slices weighing about 200 grams.

A Kagawa prefectural government official said, “The detected amount is very small, so, it will have no influence on human health.”

The official also said the prefectural government has received no reports of illnesses caused by the product.

Kouzai Bussan is now trying to collect all of the packages and plans to dispatch employees to China on the assumption that the pesticide was mixed into the product before it was shipped to Japan.

“There is a low possibility that the agricultural chemicals detected came from the mackerel themselves,” said an official of the imported food safety office of the Ministry of Health, Labor and Welfare. “I think that the pesticide was mixed into the frozen mackerel in the production process.

“Judging from the detected amount, it is unthinkable that someone mixed the pesticide into the mackerel intentionally.”

The mackerel contaminated with dichlorvos were caught and frozen in Denmark and transported to food processing company Weihai Yuwang Aquatic Foodstuff Co. in Shandong province in eastern China, Kouzai Bussan said.

The Chinese company marinates the meat with vinegar and then puts slices of the fish into vacuum packs at an adjacent marine product company Weihai Jinlin Aquatic Co.

The products are then imported to Japan by Kobe-based food wholesaler Shinko Gyorui Ltd.

Kouzai Bussan submitted two of the packages that were in its warehouse to an inspection organization on Feb. 8 under the request of its clients. On Friday night, the organization notified Kouzai Bussan that dichlorvos was detected in the frozen mackerel.

Since March last year, Kouzai Bussan has sold about 73,000 packs of the product to about 50 companies, including sushi restaurant operators.

As of Monday afternoon, Kouzai Bussan had collected only 18 of the packages. Most of the mackerel sold has already been consumed.

Kouzai Bussan is also collecting 18 other products processed in the factories of the two Chinese companies.

“Organophosphorus substances like dichlorvos cannot pass through vinyl wrapping. So it was likely mixed into the product during the period from when the mackerel were transported from Denmark to when they were processed in China’s Shandong province,” said Hideaki Karaki, professor emeritus of toxicity at the University of Tokyo. “There is a high possibility that pesticide sprayed in the factory landed on the mackerel.”