BEIJING (AP) -- Three more Chinese brands of eggs containing melamine were identified on Wednesday and leery consumers began avoiding the product, as a local government acknowledged that officials knew about the contamination for a month before it was publicly disclosed.
Authorities in the eastern Chinese city of Hangzhou recalled a brand produced by a company based in the northern province of Shanxi. In Hong Kong, government said tests on two other brands found excessive amounts of melamine.
No one has been sickened and it was not immediately clear how many eggs have been recalled.
The widening problem has exposed the inability of Chinese authorities to keep the food production process clean of toxins despite official vows to raise food safety standards.
In Beijing, egg sales dropped by at least 10 percent on Tuesday at the Xinfadi Wholesale Market, a major distribution center in the capital, the official Xinhua News Agency said.
"Everyone is scared of eating eggs right now. Who knows what other types of food is affected?" said Wen Hu, a 28-year-old software engineer living in the northeastern port city of Dalian, where China's leading egg processor is based.
"All of my co-workers, friends and family, not just those living in Dalian, have stopped eating eggs," he said. "It's one of those things that it is better to be safe than sorry."
Last week, Dalian Hanwei Enterprise Group's eggs were pulled from some Chinese stores after Hong Kong food safety regulators found excessive levels of melamine. Its Web site said that, besides the domestic and Hong Kong markets, its egg products are exported to Japan and countries in Southeast Asia.
The government of Dalian, where Hanwei is based, said in a notice dated Wednesday that it was first alerted to the problem of melamine-tainted eggs on Sept. 27 — but it did not explain the apparent delay in publicly reporting the problem.
Hong Kong authorities first revealed the test results over the weekend and the Dalian government said they were investigating how eggs came to be contaminated.
A Chinese agriculture official has said it was highly likely that melamine had been added to the feed given to the chickens that laid the contaminated eggs. The chemical is not an animal feed additive and is banned from being mixed in.
But Han Wei, director of the company, was quoted by Xinhua as saying Hanwei "has never bought melamine or added it to the feed."
He said melamine had been found in some stored feed supplied by a feed plant in late September and that his company was preparing to sue the supplier. No other details were given and telephones at Hanwei were not answered.
China's fresh eggs are mainly exported to the Chinese territories of Hong Kong and Macau, while 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 reputation of Chinese products has in the past year come under fire after high levels of chemicals and additives were found in goods ranging from toothpaste to milk powder, which was at the heart of last month's dairy crisis also centered around melamine.
Four babies died and tens of thousands were sickened in the scandal authorities said was triggered by dairy suppliers who added melamine to watered-down milk to dupe quality control tests and make the product appear rich in protein. Chinese authorities and a leading dairy producer also delayed reporting the problem for months.
Melamine, used plastics, paint and adhesives, can lead to kidney stones and possibly life-threatening kidney failure. Infants are particularly susceptible.
The Hong Kong government said late Wednesday that tests on eggs processed by Jingzhou Shuanggang Poultry Breeding and Processing Co. Ltd. of China's central Hubei province showed levels above Hong Kong's melamine limit in foodstuffs of 2.5 parts per million.
The government said earlier in the day that tests on eggs from Jingshan Pengchang Agricultural Product Co., also in Hubei, showed elevated levels.
A man who answered the telephone at Jingzhou late Wednesday said no one was available to comment.
Pan Fengxia, Jingshan'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.
In Hangzhou, authorities recalled a brand of eggs produced by Green Living Beings Development Center that contained 3.5 ppm of melamine, Xinhua said.
Mainland China has no set standard for the chemical in food. After the dairy scandal permissible levels were set at 1 part per million and 2.5 parts per million for liquid milk, milk powder and food products that contain more than 15 percent milk.
At the city's Lianhua Supermarket, an employee said all of Green Living Beings' eggs had been removed from shelves and customers had been encouraged to return the product.
"We as store workers felt shocked because we are not just store workers, but also consumers," said the employee, who would give only her surname, Liu. "We need to eat eggs as well."
Associated Press writer Min Lee in Hong Kong and Chi-Chi Zhang in Beijing and researchers Xi Yue and Yu Bing in Beijing contributed to this report.