Centre for Food Safety controller Constance Chan Hon-yee yesterday dismissed fears of serious health hazards despite the discovery of melamine in eggs, as the centre prepared to check if other major food products were contaminated. 'At present, there is no research on melamine in eggs. But there are some overseas studies showing that the health impact is small even when melamine enters the food chain,' Dr Chan said in an RTHK interview. She added that her centre would step up tests on eggs this week and would extend them to chicken meat, pork, beef and fish early next week. 'There is a possibility that if animal feed is contaminated, meat may also have a problem,' she said. Peter Wong Chun-kow, president of the Hong Kong branch of the World Poultry Science Association, said he suspected that some unscrupulous suppliers might have added the chemical to feed to artificially raise protein levels. The centre found excessive melamine levels in a sample from a pack of half a dozen Select Fresh Brown Eggs (extra large) sold by ParknShop. The eggs were from the Hanwei Group in Dalian . Chan King-ming, a professor at Chinese University's department of biochemistry, urged the government to do a general test on all food imported from the mainland. 'At first it was milk, now it is eggs. We simply do not know how widespread the problem is. And if we do not know how widespread it is, we cannot work out a meaningful strategy to tackle the issue,' he said. Young Kam-yim, of the Hong Kong Egg Merchants' Association, said eggs from the mainland had to be certified as melamine-free before they were exported, under a new practice introduced late last month. Meanwhile, Maxim's restaurant chain said last night that further tests of one of its popular dim sum dishes by the food centre did not find melamine, contrary to its previous result. A Maxim's spokeswoman said the centre took samples of mai lai cake, or steamed sponge cake, and its raw ingredients from a restaurant at the Island Resort Mall in Siu Sai Wan last Wednesday. 'The Food and Environmental Hygiene Department told Maxim's today that they did not find any melamine in the sponge cake and the raw materials,' she said. The centre ordered the restaurant to stop selling the dish last Wednesday after its tests showed it contained 3.2 parts per million of the industrial chemical. The legal limit is 2.5ppm. It was not known when those samples were taken. The Maxim's spokeswoman said the restaurant was discussing with the food authorities why there were different test results. The Food and Environmental Hygiene Department confirmed the test results were satisfactory but said investigations were still going on.