Chinese authorities said Wednesday that they were investigating how eggs came to be contaminated with the same industrial chemical at the center of a milk scandal that sickened thousands of babies, as more tainted eggs turned up in Hong Kong and the mainland.
The action follows the pulling from some store shelves of a brand of chicken eggs produced by China's leading egg processor, Dalian Hanwei Enterprise Group, after Hong Kong food safety regulators found excessive levels of melamine in eggs from the company.
The widening food scare has exposed the inability of Chinese authorities to keep the food-production process clean of melamine, the chemical that sparked the recent dairy crisis, despite official vows to raise food safety standards.
China's fresh eggs are mainly exported to the Chinese territories of Hong Kong and Macau, while processed egg products are also sold to Japan and the US, according to a February egg market report on the Agriculture Ministry's website.
The government of Dalian, the northeastern port city where Hanwei is based, said in a notice dated Wednesday that it was first alerted to the problem of melamine-tainted eggs more than a month ago – but it did not explain the apparent delay in publicly reporting the problem.
The notice said that Dalian authorities were notified Sept. 27 of tests by the customs bureau of Liaoning Province that had found melamine in a batch of export-bound eggs produced by Hanwei.
The city government said it immediately ordered Hanwei to recall the eggs deemed "problematic" and temporarily halt its egg exports. By Oct. 5, seven shipping containers that had reached Hong Kong carrying Hanwei's eggs had been recalled, while two other containers that stayed in Hong Kong were sealed off.
The recalled eggs were destroyed to prevent them from entering the domestic market, the notice said, while further tests on other batches of eggs from the company did not detect melamine.
The Hong Kong government said late Tuesday that tests on a second batch of eggs, processed by Jingshan Pengchang Agricultural Product Co., also found an excessive amount of melamine.
It was unclear how the chemical got into eggs. But a Chinese agriculture official, Wang Zhicai, was quoted by the Beijing News newspaper Tuesday, saying it was highly likely that melamine had been added to the feed given to the chickens that laid the eggs.