What's the correct syntax to use for this adjective

So I have biscuits which are made from cow's milk and the milk used in it is unadulterated and pure.

Which of these usages convey the above correctly?

1st: Biscuits made from pure cow's milk.
2nd: Biscuits made from cow's pure milk.

Answer

"cow's milk" is a set phrase, so you normally would not split it up. Therefore, the idiomatic way to say this is "pure cow's milk".