More than 1 in 4 soy sauce samples found with substance that can cause cancer, Hong Kong watchdog warns

A substance that is thought to cause cancer if consumed in large amounts has been found in 11 of 40 soy sauce samples taken by the Hong Kong Consumer Council, it said in its latest monthly report on Monday.

Soy sauces and seasonings are common condiments in Chinese dishes, but more than one in four samples tested by the council were found to contain chemical compound “4-methylimidazole”, including those from popular brands such as Yu Pin King and Tung Chun.

The chemical was identified as a possible human carcinogen by the World Health Organisation, however experts claim that the chances of it causing the disease in humans are very low.

“Hongkongers consume soy sauce almost every day,” said Consumer Council Chief Executive Gilly Wong Fung-han, urging the Centre for Food Safety to look into the matter and regulate the amount of 4-methylimidazole allowed in food, taking reference from other countries.

Currently, there is no standard for the safety and quality of soy sauces and seasonings in Hong Kong, but, for example, California law requires that businesses put a warning on product packaging against consuming more than 29 micrograms of 4-methylimidazole per day, the council said.

The amount was found in roughly 2 millilitres – under half a teaspoon – of the soy sauce sample produced by Yu Pin King and 7 millilitres of Tung Chun’s King’s Dark Soy Source in the test.

Wong attributed the existence of the possible carcinogens in the soy sauce to a common practise aimed at increasing colour intensity of the products.

To achieve this, manufacturers often add caramel colourings to soy sauces during the browning process. The ingredients were found to contain a contaminant of 4-methylimidazole.

The use of certain types of caramel colourings in food and beverages has been under increasing scrutiny in recent years, as researches found “clear evidence of carcinogenic activity in animals” due to the intake of 4-methylimidazole.

However, Wong Ka-hing, associate director at Polytechnic University’s Food Safety and Technology Research Centre said a man would need to consume at least three litres of soy sauce per day to reach the level required for cancer in the animal test.

“The reason that Hong Kong does not have such regulations is probably because the risks are extremely low,”Wong said, adding California was the only state in the US to have such regulations.

In addition to the dubious substance, the overall quality of the city’s soy sauce products were also concerning.

When assessed by Taiwan Soy Sauce Standard, only one in four tested samples in the city reached its highest Grade A level, while 10 failed to meet the lowest requirements – with four of them produced by local brand Amoy.

While many soy sauces in the market claimed to be“naturally brewed”, three samples out of 21 such products exceeded the levulinic acid content limit to attach such a label.

The Food and Safety Centre said it was studying the soy sauce samples from the survey, and would follow those which failed to comply with current regulations.

Customs said all the trade descriptions written on the packaging – including whether the soy sauces are “naturally brewed” or not – must correctly describe the product in question.

The 11 samples found to contain possible human carcinogen

Kwong Cheong Thye (Light Soya Sauce Best)

Yummy House (Premium Soy Sauce)

Konig (Excellent Soy Sauce)

Tung Chun (King’s Dark Soy Sauce)

Tai Hua (Dark Soy Sauce)

Pearl River Bridge (Golden Label Superior Dark Soy Sauce)

Yu Pin King (Premium Dark Soy Sauce)

Pearl River Bridge (Seasoned Soy Sauce For Seafood)

Tung Chun (Seafood Soy Sauce)

Imperial Banquet (Sweet Soy Sauce)

Yummy House (Premium Soy Sauce – Chili)