Your Healthy Greek Yogurt Harbors A Deadly Secret - UPDATED

Greek yogurt is healthy and good, but the process of making it creates something called acid whey. Acid whey is very bad: accidental spills of it have killed thousands of fish. But Greek yogurt is booming, so what to do with its dangerous byproduct?

For every container of Greek yogurt you see on a supermarket shelf, picture another container (or two or three) of deadly poison. It’s called acid whey, and it’s a toxic byproduct from the yogurt-making process that’s becoming a big problem for manufacturers as their product continues its assault on the hearts and minds of health-conscious Americans.

Never heard of "acid whey?" Neither had we. Modern Farmer explains:

It’s a thin, runny waste product that can’t simply be dumped. Not only would that be illegal, but whey decomposition is toxic to the natural environment, robbing oxygen from streams and rivers. That could turn a waterway into what one expert calls a "dead sea," destroying aquatic life over potentially large areas. Spills of cheese whey, a cousin of Greek yogurt whey, have killed tens of thousands of fish around the country in recent years.

The scale of the problem—or opportunity, depending on who you ask—is daunting. The $2 billion Greek yogurt market has become one of the biggest success stories in food over the past few years and total yogurt production in New York nearly tripled between 2007 and 2013. New plants continue to open all over the country. The Northeast alone, led by New York, produced more than 150 million gallons of acid whey last year, according to one estimate. (Emphasis mine.)

Possible solutions to the acid whey problem include farmers mixing it with cattle feed, incorporating it into fertilizer, or making biogas from it. Another is using it to make baby-food. But nobody’s really figured it out. As Cornell dairy scientist Dave Barbano told Modern Farmer: "Because the Greek yogurt production grew so rapidly, no one really had the time to step back and look at the other viable options."

The cheese industry has solved its whey problem by selling the stuff to companies that make body-building supplements. But the "sweet whey" produced from cheese-making is richer in protein than acid whey, and therefore easier to process.

For now, it remains a mystery what will become of all that whey. But by all means, keep eating the Greek yogurt and feeling good about yourself.

UPDATE: Greek yogurt giant Chobani released a statement today about their acid whey use:

At Chobani, we are committed to being a good community partner. That includes finding responsible uses for whey, a natural byproduct of the process to create authentic strained Greek Yogurt. We are constantly exploring the best ideas and options for beneficial whey use.

Right now, we choose to return whey to farmers, most of whom use it as a supplement to their livestock feed. Some is used as a land-applied fertilizer but only at farms that have nutrient management plans in place with the state environmental conservation agency. A small percentage is also sent to community digesters, where the whey is used to produce energy.

Total yogurt still remains silent.

[Illustration: Kelly Rakowski/Co.Exist]

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  • Con Antonakos

    How is this news? Did you know that actually GREEKS have been making Greek yoghurt for years?

  • John Huegel

    I make my own greek yogurt. The "acid whey" is a by-product of draining regular yogurt to make the thicker "greek style" yogurt. From a gallon of organic milk, I probably get 1.5 qt whey and 2.5 qt greek yogurt. As an aside, it's ridiculously easy to make your own, and it's better than store-bought.

    The acid comes from the fermentation of the lactose by the bacteria present in yogurt cultures. I tried making a traditional norse "cheese" from it but it was a bit too tart. So I just poured it in the drain, which the big guys are not permitted to do.

    Then I fed some to my dogs, both around 80-100 lbs. They went crazy over it. So now each week when I process my yogurt, my mutts are very well behaved, and patient, and wait for me to pour them some "deadly acid whey" which they very much love, and which is also quite good for their digestion.

    So yes, there are safe ways to "dispose" of the whey from making thickened yogurt. I would guess that dogs and pigs will both enjoy it.

  • facepalm

    This is a garbage article.  The author should come back and try to write a complete story.  All this is, is an attempt to be witty.  You offer no problem and only solutions, then try to make greek yogurt lovers (i hate the taste of it, its bitter/sour) feel guilty about it?

  • AL_Nemesis

    "Poison" is a bad choice of words. It is not so much a "poison" in as much as it is a potentially harmful bi-product of a process. If dumped in quantiy into a river or lake, it changes the water's pH level making it more acidic which will kill of certain species of marine life. Many processes produce by-products that are harmful in quantity like this -- which is why there are regulations around indiscriminate dumpting of them -- but they are not necessarily "poison" of the same type that, say, cyinide is a poison.  At the very least, the author should have also checked wikipedia for more information http://en.wikipedia.org/wiki/W....  At the very least, the article could follow-up on a rebuttal by a Cornell researcher regarding the "controversy" that really isn't... https://cornell.box.com/acidwh...

  • Rebelderf

    If acid whey is so potent as to kill acres of aquatic life how can it be used as feed to farm animals??

  • Ray

    Acid whey is Toxic because it removes oxygen from water, therefore, killing fish. Now mammals, like human, cow, pigs even whales get their oxygen by absorbing it through lungs and have a separate digestive system that will process the whey. Therefore harmless, although may taste a bit strange.

  • Open Source Billing

    I'm a bit confused by this post. There's really not enough information for a fully fleshed piece. You mention that acid whey is a "poison", then you say it's used for food products for animals and babies. Is that the deadly secret? What it's being used for, or that there are possibly thousands of barrels of toxic sludge sitting in some warehouse waiting to be dumped... somewhere?

    What exactly are you looking for the reader to take away here? 

  • Ray

    It's more of presenting a problem and figuring out the best solution. The stuff is only toxic because it absorbs oxygen in water. Babies and other mammals can digest it because we get out oxygen through our lungs and don't breathe water.
    The problem that the article states is that GY sales sky rocketed and therefore they ended up with tons of toxic byproduct that they hadnt figured out what to do with it. So far they have come up the solutions mentioned.

  • samcarstensen

    This article confused me. Disclaimer: I love Greek yogurt. However, I try to be socially responsible when possible. So as soon as I saw yogurt being likened to poison, my interest was piqued. But we saw absolutely zero impact from acid whey. Only from cheese whey. And it was an accidental spill at that. The ironic thing is that the only concrete applications of acid whey this article mentioned were solutions! It should come as no surprise that there are production processes for food and for everyday products that fish should not be exposed to! However, the idea that because we can't manufacture all of these things underwater they should be boycotted is such an outrageous overreaction, that it is comical. Please give us more to go with than simple fear mongering!

  • Ray

    The article itself does not indicate anything malicious, just that their was an outrageous boom in the production of GY that led to a large amount amount acid whey byproduct that wast anticipated. However the title of the article does do quite a bit of implicating which is used to attract readers like yourself.

  • Ashley Sue Bullers

    And give us more than judgmentalist self-righteousness.  Really?  "For now, it remains a mystery what will become of all that whey. But by
    all means, keep eating the Greek yogurt and feeling good about yourself."  OK, sir, I hope you only drink organic, fair-trade coffee EVER and perfectly locally-grown organic foods and meats, and don't think about driving a car.  EVER.  Or buying new clothing (and when you do, it better be from locally-sourced, organic hemp, handcrafted here in the US).  A whole myriad of things come into play when taking such a ridiculous closing comment.  I hope the writer doesn't live in a glass house, you know?