The Korea Centers for Disease Control and Prevention (KCDC) said that it has confirmed that contaminated fermented shellfish was the main culprit behind the hepatitis A outbreak this summer.

The KCDC came to the conclusions after conducting an in-depth epidemiological investigation.

The agency randomly sampled 270 of the 2,178 hepatitis A patients, diagnosed between July 28 and August 24, and surveyed whether they consumed fermented shellfish this summer. It found that 42 percent of the patients had eaten fermented shellfish during the incubation period.

KCDC also found that 80.7 percent of the 26 patients diagnosed with hepatitis A in August also ate fermented shellfish, while discovering Hepatitis A virus genes in 11 batches out of the 18 batches collected after the outbreak.

Notably, five of these genes found in the research showed close relations with the virus detected in hepatitis A patients.

The agency recommended that the public should stop consuming salted clams until it can confirm that they are safe to eat. The Ministry of Food and Drug Safety also plans to conduct a full survey of fermented shellfish distribution products this month.

As of now, the disease control agency has confirmed 10 products that have tested positive to the hepatitis A virus. Nine of them were imported from China, and one was made in Korea.

“Out of the total 10 products, weighing 37,094kg, 31,764kg has already been sold to the markets, while the remaining 5,330 kg were recovered and disposed of,” the agency said.

The KFDC asked the producers of sauced clams to halt the distribution and sale of their products for the time being and to conduct the hepatitis A virus test for each product when importing fermented shellfish.