The Food & Environmental Hygiene Department’s Centre for Food Safety (CFS) today released the first report under the second Hong Kong Total Diet Study that showed the dietary exposure to sulphites among the Hong Kong population was well below the Acceptable Daily Intake (ADI), indicating a low health concern.

In the report, sulphites including sulphur dioxide refer to a group of multifunctional food additives, particularly as preservatives and antioxidants.

The study started in February 2023, with a total of over 2,200 samples of over 180 food items collected.

Out of a total of 185 food items tested for sulphites, only 17 or about 9%, were found to contain sulphites.

Dried fruits were detected with the highest mean sulphites concentration of 240 mg/kg, followed by button mushrooms, red and white wine, and preserved vegetables, with a mean concentration of 20 to 30 mg/kg. The remaining food items with detectable levels of sulphites were found with a mean concentration of 10 mg/kg or below.

The centre said acute toxicity of sulphites is low. However, chronic excessive exposure to sulphites was found to cause local irritation of the stomach and induce adverse effects on the central nervous system in experimental animals.

Exposure to sulphites may lead to bronchoconstriction and other adverse reactions in certain population subgroups with allergic conditions.

The Joint Food & Agriculture Organization/World Health Organization Expert Committee on Food Additives allocated a group ADI of 0 to 0.7 milligram/kilogram body weight to sulphites.

The centre reminded members of the public to maintain a balanced diet to avoid excessive exposure to sulphites from a small range of food.

When purchasing prepackaged food products, consumers can refer to the food labels to know whether the products contain sulphites.