BEIJING (AP) -- A local Chinese government acknowledged Wednesday that officials knew about melamine-tainted eggs for a month before the contamination was publicly disclosed.
The revelation was the latest in a growing scandal over food products tainted with the industrial chemical and followed the recent disclosures that Chinese authorities and a leading dairy producer also delayed reporting for months that they knew baby formula had been tainted with melamine. The contamination caused kidney stones in babies and was blamed for killing four infants and sickening 54,000 children. More than 3,600 children remain sick, health officials say.
A brand of chicken eggs produced by China's leading egg processor Dalian Hanwei Enterprise Group were pulled from some stores in the country after Hong Kong food safety regulators found excessive levels of melamine in eggs from the company.
Hanwei's Web site said that besides the domestic and Hong Kong markets, its egg products are exported to Japan and countries in Southeast Asia. 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 U.S., according to a February egg market report on the Agriculture Ministry's Web site, the latest available report.
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 city government said they were investigating how eggs came to be contaminated with melamine.
Hong Kong authorities were the first to report the problem with Hanwei's tainted eggs over the weekend.
The widening food scandal has exposed the inability of Chinese authorities to keep the food production process clean of melamine, despite official pledges to raise food safety standards.
The Dalian city government's notice said it was likely melamine had been added to the feed given to the chickens that laid the eggs.
Melamine is used in making plastics and fertilizer, and is banned from animal feed. One food industry expert said it was likely added for the same reason cited in the milk scandal and last year's recall of tainted pet food: Melamine boosts nitrogen levels, making products seem higher in protein when tested.
The Dalian government notice said that local 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.
Meanwhile, more tainted eggs turned up in Hong Kong and the mainland.
The Hong Kong government said late Tuesday that tests on a second batch of eggs, processed by Jingshan Pengchang Agricultural Product Co. of China's central Hubei province, also found excessive melamine.
Pan Fengxia, the company's manager, said a retailer had notified her of the Hong Kong test result and said she was sending another sample of eggs to be tested by the Hubei provincial food safety authority.
The Hong Kong eggs from Jingshan contained melamine with a concentration of 2.9 parts per million. The legal limit for melamine in foodstuffs in Hong Kong is 2.5 parts per million.
The Hong Kong-tested Hanwei eggs contained 4.7 parts per million of melamine.
Authorities in the eastern Chinese city of Hangzhou, meanwhile, recalled a brand of eggs produced by Green Living Beings Development Center based in northern Shanxi province, the official Xinhua News Agency said. Phone calls to the company and to Hangzhou government offices rang unanswered Wednesday.
Associated Press researchers Xi Yue and Yu Bing contributed to this report in Beijing.