The Consumer Council has advised people to thoroughly wash goji berries before consuming them, in order to rinse off any heavy metal residues.

The watchdog said on Monday that it tested 27 samples of dried goji berries, and found that all of them contained heavy metals.

In two of the samples, the lead concentration was close to the maximum level permitted in Hong Kong.

The council said lead exposure can affect the mental and neurodevelopment of children and cause high blood pressure in adults.

But the chairwoman of its research and testing committee, Nora Tam, said people need not worry too much as the benefits of the nutrient-rich fruit outweigh the risks.

“We found that the heavy metal contamination problem in goji berries is not that serious… You need to consume a lot of the goji berries in order to be harmed by the heavy metals,” she said.

“If you soak the goji berries in cold water for 15 to 20 minutes, it’s possible to wash away those heavy metals on the surface of the goji berries.”

Tam also pointed out that more than half of the goji berries samples tested contained pesticides.

She called on the industry to engage responsible suppliers that adhere to good agricultural practices and are committed to mininimising the use of chemicals.