In particular, as anyone in the U.S. who reads food labels knows, whey is a very common ingredient in processed foods. So what's the problem? A partial answer:
> The concept is roughly modeled on the success that cheese-makers have had selling products derived from their own byproduct — sweet whey. Sweet whey is more valuable and easier to handle than acid whey, as it has a lot more protein, and is easier to dry because it isn’t as acidic as Greek yogurt whey. Cheese-makers have developed a lucrative business selling whey protein for use in body-building supplements and as a food ingredient. And Greek yogurt makers are eager to follow suit.
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EDIT: Another comment.
> Rejman’s workers take the shipments and try to find uses for the whey: mix it with silage to feed to the farm’s 3,300 cows; ....
Wouldn't most adult cattle be lactose-intolerant? (As human adults were until that wacky lactase-persistence mutation hit parts of Europe & Africa.) Adding whey to feed for adult cattle sounds to me like a good way to make cattle sick. OTOH, surely farmers would have figured this out.
Can anyone explain this?