Yogurt Containers and Snack Bags Made From Corn?

7 years ago
This article was written by a member of the SheKnows Community. It has not been edited, vetted or reviewed by our editorial staff, and any opinions expressed herein are the writer’s own.

Is packaging made from corn too noisy? Is it even good for the environment?

Plastic made from corn seems to be the new trend for companies that want an alternative to petroleum-based plastic packaging. Last year, Pepsico's Frito Lay introduced a new PLA (polylactic acid) bag for its SunChips snacks, and last week Stonyfield Yogurt announced new PLA containers for its multi-packs. But how well does PLA work? And is it as safe and eco-friendly as these companies would have you believe?

SunChips thought they were onto something with a bag that would supposedly break down in an industrial compost system or even in your backyard. Unfortunately, the bag turned out to be too noisy for a lot of Americans' sensitive ears. After complaints ranging from letters to entire YouTube videos, Frito Lay pulled the bag from store shelves, promising that it would work on a quieter bio-based package.

I did my own sound test in my local Safeway just to find out what all the fuss was about and posted my own little YouTube video comparing the compostable bag with a regular SunChips bag. What do you think?

The whole uproar was just irritating to me. "Come on, people," I wanted to scream. "Is the sound of your snack bag so much more important than the fate of the planet? And what about the processed crap that's in that bag to begin with?" But then I looked into PLA a little further and discovered that it's not necessarily the eco-friendly material that many of us hoped it would be.

Dangers of PLA

Besides the apparently annoying sound of the bag, there are other issues with PLA of which you should be aware.

Corn: Industrial corn farming requires huge amounts of water and petrochemical fertilizers and pesticides. And growing corn in this country is fraught with other environmentally and socially damaging practices. From monoculture farming that destroys diversity to genetically modified organisms that ensure the monopolization of the food supply by large corporations, industrial corn is a troubling business. Because of these issues, a recent University of Pittsburgh study concluded that biopolymers might be dirtier to produce than oil-based polymers.

Chemical Additives: Most people are surprised to know that PLA products, like petroleum-based plastics, contain additives that can leach, especially when heated. And the really scary thing is that besides the manufacturers of the plastic, NO ONE KNOWS what those additives are! Not the consumer, for sure. But not even the companies that contract to have their bags and containers made from the stuff. In a Stonyfield Farm webinar last week, the company admitted that it doesn't know what chemicals are added to its PLA containers because no plastic manfacturer will disclose that information. In fact, the rep who presented the webinar stated, "Plastic is the most secret industry you can imagine."

If we don't know what chemicals are added to our plastic and PLA products, how can any of us know for sure that it's safe? The FDA regulates the safety of packaging, but it doesn't require full disclosure of the additives. And we're talking about the same FDA that continues to maintain that the hormone-disruptor bisphenol-a (BPA) is safe.

Contaminates the Recycling Stream: May recyclers are concerned about the fact that if PLA containers are tossed in with other plastics for recycling, the material will contaminate the waste stream and making recycling much more difficult.

Are Stonyfield's PLA Yogurt Cups Better?

Stonyfield Farm yogurtFully aware of the list of PLA hazards that I mentioned above, Stonyfield Farm, makers of organic yogurt products, set out to create a PLA container that would be safer and less resource intensive than other PLA packaging to date. The company announced its new containers last week and was very open about the pluses and minuses. Here are a few steps that the company has taken to ensure its packaging would be healthier for people and the planet.

PLA vs. Polystyrene: Stonyfield's new yogurt cups replace the 4-ounce multipack cups that were previously made from polystyrene, the same plastic that Styrofoam is made from. Polystyrene is difficult to recycle. What's more, styrene, the basic building block of polystyrene, has been classified as a possible human carcinogen by the EPA and by the International Agency for Research on Cancer (IARC). When heated, it can leach chemicals into food. But, you might say, I don't heat my yogurt! Actually, it's already been heated in the container. But I'll get to that part later.

Because of concerns over #6 plastic, and because it could make cups out of PLA that were much lighter weight #5 plastic, Stonyfield felt that PLA was a better option.

Working Landscape Certified Corn: Aware of the problems inherent in growing corn, Stonyfield contracted with the Institute for Agriculture and Trade Policy for Working Landscape Certified corn. That means that the farmers who grow the corn agree to:

  • Grow only non-Genetically Modified (GM) crop varieties
  • No continuous annual crop production on same acreage
  • Soil testing to assure that nutrients are used efficiently and are not likely to leach or run-off
  • No use of chemicals that are known human or animal carcinogens, including atrazine
  • Use of cover crops to minimize soil erosion
  • Creation of a farm plan that includes information on biodiversity, energy use and greenhouse gas emissions.

Now, the corn Stonyfield actually receives is not necessarily the certified corn. The IATP system is an offset program. Stonyfield contracts for the amount of certified corn it needs, and that amount enters the system, whether Stonyfield or some other purchaser gets it.

Chemical Additives: Stonyfield doesn't know what chemicals have been added to its PLA. Like I mentioned above, plastics manufacturers keep that information to themselves. What the company does know is that the containers are made from 93% PLA, 4% titanium dioxide -- a colorant, and 4% other additives. And Stonyfield wanted to make sure that 4% was as safe as possible. So it decided that even if it couldn't specify what chemicals would go into the plastic, it could ban the chemicals it didn't want.

With the help of an environmental consulting firm, the company came up with a list of several classes of chemicals and over 2,500 specific chemicals that would be banned from its containers. According to Stonyfield, their packaging contains no phthalates, polybrominated materials, PVC, BPA, or any of over 2,500 chemicals shown to be toxic (carcinogens, mutagens, reproductive toxicants, and endocrine disruptors) by several different U.S. and international agencies.

So is the plastic safe enough?

It's impossible to know for sure. The fact is that new chemicals are released to the market constantly. If we don't know exactly what's in the plastic, we can't make truly informed decisions about whether its safe enough for us and our families. Personally? I don't buy food in any kind of plastic packaging for just this reason. But Stonyfield has done the best it can with the information available.

Waste -- Downstream vs. Upstream: Unfortunately, right now there is no way to recycle Stonyfield's new PLA containers. They can't be composted because of the mixed materials, and even though there are two PLA recycling facilities in existence, Stonyfield can't do it yet because the multi-pack lid is made from a different kind of plastic.

The company says they are working on these issues. For now, they claim the upstream benefit of the new packaging outweighs the downstream waste issue. In a life cycle assessment performed by Roland Geyer from UC Santa Barbara, PLA outperformed polystyrene in the areas of greenhouse gas emissions and human toxicity. In fact, the new cups have 48% lower global warming potential than the old ones. And that is why Stonyfield is comfortable releasing them without a recycling infrastructure in place yet.

"Cooking" yogurt in plastic: Plastics leach the most when they are subjected to heat. And while you are probably not going to put a plastic container of yogurt into the microwave, Stonyfield's yogurt cups are filled while the yogurt is still hot. 100°-108° F, to be exact. Why? Because that is the temperature needed to grow the little bugs that make the yogurt. The cups are filled with the hot milk as well as the yogurt culture, and the yogurt sets right there in the plastic cups. If there are chemicals that can leach from the plastic, that's the time they'll do it.

Not all yogurt companies fill their yogurt cups with hot milk, but all the big ones do. During my visit to Straus Family Creamery, a local yogurt company I visited and blogged about last year, I learned that that company vat sets their yogurt. The milk is cultured in big stainless steel vats, and the plastic yogurt cups are not filled until the yogurt is finished and has been cooled to 40°F. As you can imagine, Straus makes its yogurt in much smaller batches than Stonyfield. It's not attempting to outdo the Yoplaits and Dannons of the world.

Is Any Packaging Necessary?

What if we didn't need a disposable package in the first place? While the PLA package might be better than petroleum-based plastic, it still requires materials and energy to create and facilities for disposable. There are already two options that negate the need for plastic yogurt cups. The first is not available everywhere. But the second... anyone could do.

Returnable Containers: St. Benoit is a small yogurt company in the Bay Area. It sells its yogurt in returnable glass and ceramic containers. Just like glass milk bottles that are available in some places and can be returned to the store, St. Benoit's containers carry a deposit which is refunded to the customer when the jar is returned. There's no extra fuel used to return the container to the store because customers just bring them back during their regular shopping trips. Zero waste (except for a plastic security seal around the lid).

Make Your Own: Do you know how easy it is to make yogurt yourself? It's so simple that I achieved perfection the first time I tried. I made it in a Thermos. Here are the homemade yogurt instructions I followed. All that is required is milk, a tablespoon of yogurt from a previous batch (or commercial yogurt if it's your first time), a thermometer, and a thermos. Fruit or sweeteners are a plus. And you get the whey along with the yogurt, which can be used in all sorts of ways. (Pun acknowledged but not necessarily intended, unless you like puns.)

The Bottom Line

To me, bio-based packaging is a step in the right direction, whether for chips, yogurt, or other foods. But it's not the best solution. Let's not forget that we do have other choices. We don't have to opt for the mass market. I'd rather make my own yogurt and snacks and avoid the plastic packaging altogether.

But what do you think?

Beth Terry
Live Life with Less Plastic!
Twitter: @fakeplasticfish
Facebook: FakePlasticFish

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