BEIJING—The European Union banned imports of baby food containing Chinese milk Thursday as a toxic chemical that was illegally added to China’s dairy supplies turned up in candy and other Chinese-made goods that were quickly pulled from stores worldwide.

The 27-nation EU adds to the growing list of countries that have banned or recalled Chinese dairy products because of the contamination, which has killed four Chinese babies and sickened 54,000. In addition to the ban, the European Commission called for more checks on other Chinese food imports.

Outside Shanghai, three zoo babies were found to have developed kidney stones after being nursed with tainted milk powder for more than a year. A lion cub and two baby orangutans were sickened after drinking infant formula made by the Sanlu Group Co., said Zhang Xu, a veterinarian with the Hangzhou Zhangxu Animal Hospital.

Sanlu is at the center of the tainted milk crisis.

Chinese baby formula contaminated with melamine has been blamed for the deaths and illnesses in China. Health experts say ingesting a small amount of the chemical poses no danger, but melamine—used to make plastics and fertilizer—can cause kidney stones and lead to kidney failure. Infants are particularly vulnerable.

In the southern Chinese territory of Macau, authorities found melamine in samples of a popular chocolate-filled Koala-shaped cookie made by Lotte China Foods Co. Tests found melamine in the cookies were at levels 24 times the safety limit, the Macau government reported. The company is a member of Tokyo-based conglomerate Lotte Group.

Hong Kong supermarkets also removed the popular Japanese brand of chocolate-filled cookies from shelves Friday.

All European Union imports of products containing more than 15 percent of milk powder will have to be tested under the new rules due to come into force Friday.

Food safety experts in the EU, which imports about 21,500 tons of Chinese confectionary products, said there is only a limited risk in Europe from the food imports. But the European Commission says it is acting as a precaution in the face of the growing health scare.

The World Health Organization and UNICEF, the U.N. Children’s Fund, issued a joint statement Thursday expressing concern about the crisis.

“Whilst any attempt to deceive the public in the area of food production and marketing is unacceptable, deliberate contamination of foods intended for consumption by vulnerable infants and young children is particularly deplorable,” the statement said.

Melamine has been found in infant formula and other milk products from 22 Chinese dairy companies. Suppliers trying to cut costs are believed to have added it to watered-down milk because its high nitrogen content masks the resulting protein deficiency.

“We also expect that following the investigation and in the context of the Chinese government’s increasing attention to food safety, better regulation of foods for infants and young children will be enforced,” the U.N. statement said.

The statement also called for more awareness of the benefits of breast-feeding. That has become less common in recent years in China as working mothers switched to powdered baby formula.