捐赠的牛奶可能是罪魁祸首：最近对老鼠的实验室研究表明，给老鼠喂食酪蛋白（一种牛奶蛋白）时，短暂接触过黄曲霉毒素物质的老鼠容易患肝癌。

The donated milk was probably to blame: recent laboratory research on rats has shown that rats briefly exposed to the substances aflatoxin tend to develop liver cancer when fed casein, a milk protein.

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这种物质一般从小牛的胃中采集而来，里面含有的多种酶能够切断牛奶中的一种蛋白——酪蛋白的水溶性末端。

Then they add a substance usually harvested from veal stomachs called rennet, a mixture of enzymes that slice the ends off caseins, a kind of milk protein.

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而它的成分是酪蛋白，一种牛奶蛋白。

That ingredient is casein, a milk protein.

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