Whether the pasteurization process (aluminum vats and piping) contributes to the amount of aluminum in milk, or it involves the feed the animal is eating, is unknown.
(the pasteurization process; contributes; to the amount of aluminum in milk) (it; involves; the feed the animal is eating) (the feed; is eating; the animal)
the pasteurization process it the feed
contributes involves is eating
to the amount of aluminum in milk
the feed the animal is eating
the animal