Hong Kong’s Food and Health Bureau has ordered two Japanese infant formula manufacturers to voluntarily recall their products sold in Hong Kong, noting an insufficient level of iodine.

The head of the bureau said Wednesday that the level of iodine in the powered milk produced by Japan’s Wakodo and Morinaga is just a third of the standard recommended by the World Health Organization.

The agency explained that a lack of iodine has negative effects on children’s thyroid functions and brain development, and it has advised parents not to feed the Japanese powered milk to their kids.

The Hong Kong government will also examine other infant formula products by the end of next June.