ROBERT SIEGEL, HOST:
If you've ever checked the ingredient list on a power bar or a high-protein smoothie, you've likely seen these words: whey protein concentrate. You'll find this mysterious ingredient in lots of prepared foods.
As NPR's Dan Charles reports, it comes from what cheesemakers used to throw away.
DAN CHARLES, BYLINE: When Eric Bastian was a boy on a dairy farm near the small town of Aurora, Utah, he'd load 10-gallon cans of milk on the back of a pickup truck and drive them to the local cheese factory.
ERIC BASTIAN: And we would dump the milk on the back side of the factory.
CHARLES: Inside every cheese factory, milk gets separated into solid curds and liquid whey. For every pound of curds there are nine pounds of whey. But the little factory in Aurora had no use for the whey. So, Bastian and his father would wash out their milk cans...
BASTIAN: And then we'd load them back on the truck drive and come around on the side, and fill those cans back up with whey and take it home to feed the pigs.
CHARLES: As cheese factories grew, though, and farming became more specialized, there were a lot of places where this kind of labor-intensive recycling of whey didn't happen.
BASTIAN: It was being dumped out onto fields. Some wheys were being deposited into lakes and rivers, so there was contamination of some of our water streams.
CHARLES: But now there's a whole new way to deal with whey.
(SOUNDBITE OF MACHINERY)
CHARLES: A river of milk flows into the Cabot Cheese Factory in Middlebury, Vermont; 1.6 million pounds of milk every day. Tim Opper, who's director of process technology here, shows me how the whey drains away from the curds as they're carried along on a massive, slow-moving, belt that works like a sieve.
TIM OPPER: The cheese curds come on the belt, separating the whey from the cheese. And underneath, there is a reservoir collecting that whey and we're pumping it off.
CHARLES: Alongside this cheese-making factory there's another one. It looks a lot bigger and more high-tech than the cheese plant, actually. It's a whey refinery.
(SOUNDBITE OF MACHINERY)
CHARLES: Huge rooms are filled with of shiny pipes funneling this yellowish, watery liquid through filters. The pores in these filters are so tiny and precise, they can trap big molecules like the long chains of amino acids we call proteins, while the smaller water and sugar molecules flow right through. It's all dedicated to dividing this river of whey into increasingly narrow purified streams - pure sugar; lactose, for instance, or concentrated protein.
There are even ways to fish out one specific protein, if it's valuable enough.
(SOUNDBITE OF MACHINERY)
OPPER: This is the lactoferrin processing room.
CHARLES: Lactoferrin is a protein that helps the body use iron and also fight infection. It's common in human breast milk but there's not much in cow's milk. From the million and a half pounds of milk that goes through this factory every day, the equipment in this room captures just 120 pounds of lactoferrin.
OPPER: We're just stripping out that single molecule and collecting it, processing it and drying it into a powder.
CHARLES: In bulk form that powder is worth about $225 a pound. When it's packaged as a nutritional supplement, some consumers are paying $50 for just an ounce of it.
Now, the people from Cabot Cheese say these sugar and protein products are a nice boost to their bottom-line, but their main product is still cheese. American cheese consumption is growing. But the bigger the cheese factory, the bigger the stream of whey and the more profitable the business of whey refining.
And Eric Bastian - the man who grew up hauling 10-pound cans of milk to a little cheese factory in Utah - now works for a company that runs some of the biggest cheese factories in the country: Glanbia.
Glanbia has factories that handle 10 million pounds of milk a day in the new mega-dairy states of Idaho and New Mexico. Those factories treat milk almost like crude oil, a raw material you can break apart into separate, more valuable products.
Bastian is director of research for Glanbia Nutritionals, which handles the whey processing.
BASTIAN: Depending on the markets, in any given year, the whey might actually be more valuable than the cheese.
CHARLES: That's partly because the filtering technology has improved so much, he says. But markets for whey products also have expanded. The sugar, the lactose, may end up in chocolate or baked goods. But most of it gets shipped to Asia; it's often used in infant formula.
But the big surge in demand is for the concentrated protein. It started with athletes.
BASTIAN: The bodybuilders got into this in a big way. And they found that in terms of bulking up, putting muscle on their bodies, that whey protein was the best protein they could find.
CHARLES: More recently, this protein has spread into products for ordinary consumers. There's been a boom in high protein drinks; thicker, protein-rich versions of yogurt; energy bars.
BASTIAN: It started with Power Bar but now you have a whole slew of protein bars. Luna, Balance. You know, the list goes on and on of different protein bar manufacturers out there that are putting protein into these bars. And these dairy proteins are a significant portion of that.
CHARLES: In fact, this is where more and more of the country's milk is going. Per person, Americans are drinking less of it. Instead, they're eating both curds and whey. Dan Charles, NPR News.