Authorities have blamed dairy suppliers, saying they added the industrial chemical melamine to watered-down milk to dupe quality control tests and make the product appear rich in protein.

• 当局指责牛奶厂家，说他们添加工业用的化工原料三聚氰胺以便加水稀释牛奶，骗过质量控制，以使产品看起来富含蛋白质。