WITH the annual Dragon Boat Festival falling on tomorrow, food safety authorities have asked the public to be wary about consuming zongzi, or glutinous rice dumpling, after inspections found excessive amounts of chemicals in some zongzi.

According to a random inspection carried out by the authorities in Yuyao, Zhejiang Province, earlier this month, the illegal practice of dyeing zongzi leaves is widespread.

The city’s food authorities selected four types of zongzi produced by three local factories and found three of them to have green leaves containing excessive amounts of copper. The worst zongzi contained 34 times more copper than the national standard.

The China Consumer Association, which also conducted inspections, said many leaves used to wrap zongzi contained chemicals surpassing the national standard.

Excessive chemicals included copper sulphate and copper chloride. Officials with the association said the harmful chemicals were used to keep the leaves looking green and fresh.

“The bamboo or reed leaves used to wrap zongzi are fresh and green when they have just been picked but will gradually turn yellowish green or yellowish brown after a period of time,” explained Shen Xiangkun, an expert with the Henan Food Research Institute.

Shen said the practice is a serious violation of the Food Hygiene Law, which bans industrial materials from being used as a food additive.

“The leaves dyed by copper sulphate or copper chloride contain some metal elements which will penetrate into the zongzi and cause great damage to the health. The worst chemicals might lead to cancer or renal failure,” Shen said.

The Dragon Boat Festival falls on the fifth day of the fifth lunar month, and along with paddling frantically across the local lake, eating zongzi is the big tradition of the day.

The association suggested people buy established brands of zongzi at reliable supermarkets and stores. (SD-Agencies)

Three ways to tell if a zongzi is poisonous:

Appearance: Poisonous zongzi leaves look fresh and green, while normal ones look dark.

Odor: Poisonous zongzi leaves do not have the same unique scent of normal leaves after boiling. Instead, they give off a mildly sulphuric odor.

Color of boiled water: Water containing poisonous zongzi will turn green after boiling, while normal zongzi water turns yellowish.