June 10, 2011
The nation’s drug watchdog on Friday publicized a draft national standard of sulfur dioxide residue in Chinese herbal medicine, which is open for public opinion until Sept. 9 this year.
The maximum amount of sulfur dioxide residue is 400 mg in one kg of each of 11 specified kinds of herbal medicine, such as Chinese yams, Gastrodia elata and Codonopsis pilosola, according to the draft standard unveiled by the State Food and Drug Administration (SFDA).
The standard provides a 150-mg-per-kg limit for all other kinds of herbal medicine.
Fumigation with sulfur is used as a way of drying some herbal medicine by growers, and currently have no alternative that is both cheap and convenient.
The SFDA said it doesn’t favor the drying herbal medicine through fumigation with sulfur and urges research efforts to invent new alternatives.
According to the World Health Organization, the tolerable maximum amount of sulfur dioxide that a human body can take in one day is 0.7 mg per kg, which means that an adult of 60 kg should not take in more than 42 mg of sulfur dioxide a day.
Long-term exposure to high amounts of sulfur dioxide can cause damage to human body, especially the respiratory system, according to experts.