On 5 June, the Japanese Foreign Ministry’s Asian and Oceanian Affairs Bureau Chief Kenji Kanasugi met the South Korean Foreign Ministry's Director-General for Asian and Pacific Affairs Kim Jung-han in Tokyo.
Kim told Kanasugi that Tokyo should not use a recently announced stiffer inspection scheme for flatfish and shellfish as a disguised discriminatory measure against South Korean seafood. Korea has maintained restrictions on Japanese seafood imports after the 2011 Fukushima nuclear accident even while some other nations have relaxed their bans.
Japan’s Ministry of Health, Labour, and Welfare issued a notice to the media on 30 May about the revision of its monitoring of flatfish and shellfish imported from South Korea. It said at the time that the change was not a retaliatory measure, but rather was due to an increase in the rate of food poisoning last summer.
Under the new scheme, the sampling rate for flounder imported from South Korea to test for the parasite Kudoa septempunctata will double, from 20 percent to 40 percent. The rate of sampling South Korea sourced ark shell (or blood clam), comb pen shell (Atrina pectinate, Japanese: tairagigai), Japanese egg cockle (Japanese: torigai), and sea urchin for Vibrio parahaemolyticus will also be doubled, from 10 percent to 20 percent of the total amount imported. The change applies to chilled raw seafood. If it is believed that the probability of a violation is high, the government may sample 100 percent of the imported seafood.
When an olive flounder parasitized by a large number of Kudoa septempunctata spores per gram of muscle tissue is eaten by a human, the parasite causes transient diarrhea and vomiting several hours after eating. The symptoms are not severe and recovery is rapid. Cases of Kudoa food poisoning tend to occur most often from August to October, with only a few cases from November to May.
Eating uncooked olive flounder sashimi is the cause of many cases of Kudoa food poisoning. Such poisoning can be prevented by freezing or cooking flounder, but freezing reduces the quality of the meat. In Japan, there have been several outbreaks of food poisoning per year caused by flatfish imported from South Korea: in 2015, 8 outbreaks with 62 patients; in 2016, 10 outbreaks with 113 patients; in 2017, 5 outbreaks with 47 patients; and in 2018, 7 outbreaks with 82 patients.
The main type of flounder imported from South Korea is olive flounder (Paralichthys olivaceus). It is the most valuable aquaculture product for the country, raised in land-based tanks. More than half of the national production comes from Jeju (Cheju) Island, which has the benefit of underground seawater that keeps a steady temperature of 16 to 18 degrees C, close to the optimal 21 degrees for olive flounder. South Korea produces around 50,000 metric tons of flounder. About 10 percent of this is exported to Japan, where it holds about a 50 percent market share – the other half being mainly domestic.
Regarding shellfish, last year, vibrio paralytic food poisoning caused by imported sea urchin occurred in Japan. Vibrio parahaemolyticus is a pathogenic microorganism that proliferates in a short time, so it requires hygiene control during processing, distribution and storage. It grows rapidly at room temperature. The incubation period is eight to 24 hours. Symptoms include stomach ache, watery diarrhea, fever, and vomiting. For fresh food and seafood, the standard for the number of Vibrio parahaemolyticus is 100 or less per gram of sample.
