食用含有极高浓度的三聚氰胺的饲料的鸡所产的蛋含有的这种有潜在毒性的污染物的浓度仍然没有超过美国食品与药品管理局(FDA)规定的上限。这是首个检查了三聚氰胺污染的饲料对产蛋母鸡的影响的研究得出的结论。它发表在了美国化学会的《农业与食品化学杂志》双周刊上。

张丽英及其同事指出，由于2008年中国某些食品制造商非法地向奶粉加入常用于制造塑料的三聚氰胺从而在蛋白质含量方面造假，三聚氰胺引发了一场公共卫生争议。当局从那以后在食用被三聚氰胺污染的饲料的鸡所产的蛋中发现了浓度过高的三聚氰胺。然而，在此之前科学家并不知道在这个过程中有多少三聚氰胺可能在鸡蛋中积累。

为了提供确定这种风险的科学基础，张丽英的研究组让下蛋的母鸡食用被三聚氰胺污染的鸡蛋，结果发现饲料中三聚氰胺的增加导致了鸡蛋中这种物质含量的增加。然而，这些鸡蛋中的三聚氰胺浓度都没有超过FDA的最高可容忍水平——食品中的浓度为2.5ppm（百万分比）。饲料中三聚氰胺的最高浓度大约是100ppm，这导致了鸡蛋的污染水平大约是1.45ppm。这组科学家提出，饲料中的三聚氰胺污染水平小于100ppm将不会导致食品安全的潜在风险。

原文出处：

J. Agric. Food Chem. DOI: 10.1021/jf904205y

Deposition of Melamine in Eggs from Laying Hens Exposed to Melamine Contaminated Feed
Yiqiang Chen, Wenjun Yang, Zongyi Wang, Yong Peng, Bin Li, Liying Zhang* and Limin Gong*

State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China

The deposition profile of melamine was studied in eggs obtained from laying hens fed melamine contaminated feed. A total of 180 laying hens were divided into five groups and were fed diets spiked with 0, 5, 25, 50, or 100 mg of melamine per kg of feed. Eggs collected on days 1, 3, 5, 7, 9, 11, 13, and 15 were analyzed by a gas chromatography?mass spectrometry method, which was fully validated for melamine analysis prior to use. For each treatment group, the melamine level in the eggs was similar from day 1 to day 15 (P > 0.05), suggesting that laying hens did not accumulate melamine for later deposition in eggs. The average melamine concentrations in eggs were 0.00 (below limit of detection), 0.16, 0.47, 0.84, and 1.48 mg/kg for the 0, 5, 25, 50, and 100 mg/kg treatment groups, respectively, which demonstrated an apparent dose?response relationship, and a safety threshold of 164 mg/kg melamine in the feed of laying hen was estimated when a maximum tolerance level of 2.5 mg/kg melamine in egg was adopted. These results provide a scientific basis for the risk assessment of melamine in feeds fed to laying hens.