Of the 1,737 batches of kimchi imports from China to South Korea made last month, 88 percent, or 1,525, contained aspartame, a common artificial sweetener that is likely to be declared by the World Health Organization as a possible carcinogen.

The declaration would put aspartame on the third-highest of the WHO's four categories for cancer causes, behind carcinogenic and probably carcinogenic and means there is limited evidence it causes cancer. Aloe vera, mobile phones and carpentry are also in this category.

Traditional pickled vegetables such as kimchi are also in this category, but the use of aspartame and its classification as a possible additional risk -- albeit at much higher amounts than are present in kimchi -- is still likely to unnerve consumers.

According to the Ministry of Food and Drug Safety, some 22,632 metric tons of Chinese-made kimchi worth nearly $12.63 million were imported into South Korea last month.

Local kimchi producers such as Daesang Jongga, CJ Bibigo and Pulmuone use plum extracts and sugar to sweeten their kimchi.

Industry sources said that the reason so many kimchi producers in China use aspartame instead of sugar or corn syrup is to keep the kimchi from losing its crunchiness or ripening too fast on its way from the factory in China to Korean customers.

A cancer research arm of the WHO is expected to list aspartame, used in diet sodas and other food and drink products as “possibly carcinogenic to humans” this month for the first time, Reuters reported last week.

The International Agency for Research on Cancer (IARC) assesses whether something is a potential hazard or not, and a separate WHO expert committee on food additives, called JECFA (the Joint WHO and Food and Agriculture Organization’s Expert Committee on Food Additives), advises on how much of a product a person can safely consume.

JECFA, whose views are widely shared by national regulators, is scheduled to announce its findings on aspartame use on July 14, according to news reports.

Since 1981, JECFA has said aspartame is safe to consume within accepted daily limits – an adult weighing 60 kilograms would have to drink between 12 and 36 cans of diet soda, depending on the amount of aspartame in the beverage, every day to be at risk.

The news that aspartame will be listed as “possibly carcinogenic” has food and beverage companies on alert, with the local makgeolli sales already taking a hit after news reports that much of the traditional Korean rice wine contain aspartame.

And according to the Ministry of Food and Drug Safety, an adult weighing 60 kilograms would have to drink 33 bottles of makgeolli to reach the maximum acceptable daily amount of aspartame. That's the alcoholic equivalent of about five bottles of whiskey.

Alcohol is included in the WHO's top category of cancer risk, as a confirmed carcinogen.