SINGAPORE - A test on disposable chopsticks sold here shows they are generally safe for use and do not contain excessive amounts of sulphur dioxide residue, said the Consumers Association of Singapore (Case) in a statement on Wednesday (Nov 7).

Sulphur dioxide is often used as a bleaching agent and to prevent the growth of mould and pests in disposable wooden or bamboo chopsticks.

Excessive sulphur dioxide can harm the human respiratory system, said Case.

The test on 20 samples of disposable chopsticks showed less than 400mg/kg of sulphur dioxide in all samples. A range of between 7mg/kg and 364mg/kg was detected.

There is no specific standard regulating the amount of sulphur dioxide residue in disposable chopsticks in Singapore, said Case, but it noted that the regulatory authorities in China and Taiwan limit the amount to 600mg/kg and 500mg/kg respectively.

Case added that the chopsticks tested were from department stores, supermarkets and stores in the heartland areas. Chopsticks provided for takeaways from eateries were excluded "as a form of control and also because of traceability issues".

While Case said that disposable chopsticks here are generally safe for use based on the test results, it advised consumers to avoid using chopsticks that appear too white.

"As sulphur dioxide is used as a bleaching agent, disposable chopsticks that appear too white are likely to have been bleached before, thus potentially containing sulphur dioxide," said Case.

It added that the public should avoid disposable chopsticks that give off a pungent smell as this may indicate chemical use, and that the chopsticks are meant for single-use only.

Mr Loy York Jiun, executive director of Case said that the test was conducted following reports in the region about harmful chemicals found in disposable chopsticks.

He cited an incident a few years ago where Taiwan's Food and Drug Administration ordered disposable chopsticks to be removed from the shelves after they were found to contain deadly toxins.

"Hence, Case felt that there was merit in looking into this matter to determine the safety of disposable chopsticks in Singapore," he said.