It is perfectly acceptable to use the plural of non-count nouns when discussing multiple different types of something.

[Here is are some example usages of *milks*:](http://books.google.com/books?id=nS5EAAAAYAAJ&q=%22three+milks%22&dq=%22three+milks%22&hl=en&sa=X&ei=sh9rUZzQI6G7igLn5oD4BQ&ved=0CF4Q6AEwCA)
> Daily tests of  the butterfat contents of the three milks showed much wider variations ...

> The season's results of the casein analysis of the three milks are shown ...

*Fish* and *fishes* is another example that comes to mind.