Is cornstarch plastic packaging (PLA) compostable or recyclable?
Marks and spencer cornstarch packaging
A year ago I wrote to Marks and Spencer about their cornstarch derived plastic packaging. As part of their ‘plan A‘ (because there is no plan B), Marks and Spencer announced they would be using more and more of this cornstarch derived plastic for packaging their products.
I asked whether I could just throw this packaging in the bin (yeah right; as if) or whether it needed something special doing with it.
Neil Brown, customer advisor at that time, wrote:
Cornstarch packaging
“The beauty of cornstarch packaging, is that you can dispose of it exactly how you like and the result will still be environmentally friendly. If you would like to, you can put the packaging onto a compost heap or send it to landfill, and after seventy two days it will have completely broken down.”
Well that sounds just too good to be true, doesn’t it?
I then responded with the following questions:
- Are you using this packaging for all your goods?
- Are there any disadvantages to it?
- if it breaks down after 70 days, how long a shelf life can products have in it?
- How does it compare to petroleum based plastic?
Convenience foods
Neil had left he building by the time I followed this up a few weeks ago, so Alex Hawkins took over to help me with my first question. I was then referred to a packing technologist for the rest. In response to the first question, Alex said
“We don’t use corn starch for all our packaging at the moment - it is mainly used for products in our Food To Go range such as sandwich containers”.
The rest of the answer followed duly, a week later, as promised.
12% packaging reduction
“Further to my e-mail on Wednesday, I have now heard back from our Packaging Technologist. The following is quite a long and detailed response, and I hope it will answer all your questions. Firstly, I would like to take this opportunity to update you and report that we have completed our second year audit for Packaging Reduction and are currently at 12% reduction across all of Foods.
Cornstarch, as we have stated previously, is a compostable material. We continue to support these new and innovative materials and commit to using them wherever practically possible.
Compostable PLA
You will appreciate that as the materials are new, our knowledge is constantly increasing. Since our last e-mail, we have needed to change our composting logos to reflect the different types of composting that is available. The starch in cornstarch packaging is known in the industry as PLA. PLA is compostable, but practically, the ideal conditions are in industrial composting facilities rather than in customers’ homes.
Although they will eventually compost at home, we have had some customers experience difficulties in getting the packaging to compost properly. We believe this is due to the customers not being able to achieve ideal composting temperatures for a sufficiently long enough period.
We appreciate that this news will be disappointing given our last response. However, we only use PLA in window patches on sandwiches, where we advise customers to recycle the pack - PLA in small quantities on cardboard does not represent an issue for cartonboard recycling mills. (my bolding and italics - this surprised me; you?)
Limitations of cornstarch packaging
Sadly we cannot use cornstarch packaging across all foods as there are many limitations to the material, the most important being that they are not suitable for use in the microwave or conventional oven. This immediately severely limits their applications.
We also have to consider functional barriers in order to meet shelf life and PLA is not always suitable for all products. We continue to research Home Compostable materials, but we have decided, in light of recent learnings, and in order to provide real clarity on this complex subject, only to use Home Compostable materials for the time being. We have decided not to use the so called ‘degradable’ materials and ‘oxy-degradeable’ materials as we believe them to be misleading. (again, my bolding and italics - interesting stuff in the light of recent conversations about biodegradable plastic bags carrying more ecological harm than good here at my zero waste)
Protection of food
To sell different food formats we need to consider different material types. In an ideal world we would be able to consider one material against another with only environmental considerations in mind. However, as a food retailer we must consider the protection of food first and foremost.
In fact to incur food waste is significantly more damaging to the environment than packaging utilisation. (would love to hear your thoughts on this) As such, we do use plastics on many products and will continue to do so for the foreseeable future.
Benefits of plastics
Plastics are lightweight so reduce transport costs, they have an excellent carbon footprint, (??) they have good functional properties and come in a range of types that are suitable for both the chill chain, the microwave and the conventional oven.
We can include a recycled post consumer waste content and as such, we create a recycling waste stream for the materials that encourages Local Authorities to collect them.
I hope that response has been helpful and please do feel free to conact me with any further questions.”
So there you go. I would love to know what you think and if you have any further questions to put to Marks and Spencer about their packaging; I found their response very interesting and it bought up some key points for me.
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Hi Mrs Green,
M&S have given a full explanation of the shortcomings of PLA, which is commendable. However, it is disappointing that home compostable material may never be found. What we are left with is the current mess where plastic waste collects in household bins.
An alternative would be for M&S to take back all the PLA for industrial composting, using a return fee system. This would stop the otherwise inevitable waste result.
The food waste mantra is dragged out again to dodge responsibilty for their wasteful practices, which councils and householders have to pay for. That situation will not last indefinitely. They should look at reusable/refillable systems, using containers, which produce Zero Waste.
Excellent piece and investigation.
I still concern myself with what these things end up as. Dredging up my old science, ‘matter cannot be created or destroyed’, so you have to end up with something. The question is what… and where.
In a worst case (IMHO) you end up with a plastic soup, that may not choke a turtle but still doesn’t sound great in the water table. And I have to ponder what gasses are given off during the process too; I doubt they are always benign, GHG-wise.
I’ll have to revisit my little investigation a few years back at the time of the plastic bag bans.
Frankly reuse is optimal, but I would say that, and concede it is not always practical (though I am pondering how bulk schemes may work for certain products, and indeed one is being trialled by ASDA).
Which brings us back to effective recycling. Trouble is, that means sensible coordination and cooperation between manufacturers, retailers, LGAs and… the public. Not working out so well so far.
If we are to have these breakdown-style products ‘in the mix’ they do need to be separated and delivered to appropriate processing facilities… just as one should any other recyclate. However, the plethora of options countrywide, from pack types to disposal systems, coupled with all the competing label systems, does not seem designed to encourage an already less than motivated public to act in complement.
I am having a rather unique ‘problem’ with my waste plastics, which I retain to find uses for, in that some I have stored are indeed breaking down, which makes them useless to me. Hence I am having to train up on the various labelling options to split them out. Frankly, embossed black on black doesn’t help this much, especially as at my age my eyesight is no longer what it used to be.
The information provided to you by M&S is quite accurate in its assessment of PLA. What is a little disappointing is that the company introduced the material to the market BEFORE they fully researched its compostability. The producer of that material - NatureWorks in the USA - makes it quite clear in their marketing literature that it can only be effectively composted in industrial systems and not in home heaps.
Unfortunately, it sometimes seems that UK retailers allow their packaging decisions to be made by marketeers rather technologists, which is a little disappointing. Last year I met a packaging specialist for Tesco - he said then was the only person in the company’s packaging team with plastics expertise!
However, the real issue around packaging is that what the consumer sees as a waste of money is a real cost saving measure for the growers and retailers. And in agricultural and retailing environments, cost is direclty related to energy use and so to carbon dioxide emissions. The UK organisation that is charged with minimising waste - WRAP - has recognised this and acknowledged that the environmental harm caused in the UK by packaging is very small compared to the harm caused by food waste.
WRAP estimates that more than one third of food sold in the UK is wasted. If we can address this problem we can reduce emissions released during the growing, transportation and packaging of food by much more than can be achieved by playing around with the type of packaging used.
@Chris: HI Chris, Do you never tire of the plastic packaging industry justifying their wasteful practices, by the preposterous claim that the material is to reduce food waste for the consumer. The truth is it is used purely to raise profits for the retailers. Meanwhile, householders and councils foot the bill. This is wrong and should be rectified.
Another factor for you to consider is fact that I do not use your plastic waste and have absolutely no food waste. This shows your food waste mantra to be a false premise.
The Zero Waste perspective is to aim to reduce waste, mainly plastic in my experience, by using reusable /refillable systems. This should be your target as well.
@John Costigane: Hi John, it would be a good idea for M&S to offer a return deposit on their packaging for composting.
@Peter: Hi Peter; what fascinating stuff - about some of the plastics degrading. Worrying too - it’s these types that concern me most of all; the ones that just break down into slivers
@Chris: .Hello Chris; thank you for taking the time to comment. It’s good to hear your opinion on this.
It is a shame that composting options were not more fully investigated by M&S before this cornstarch packaging hit the shelves.
I understand the argument about packaging preventing food waste, but am yet to be convinced with objective assessment, research and figures.
My take is that the problem lies with our society.
We are extremely wasteful through total lack of care. Food doesn’t go off any quicker than it has done for millennia; but we live in such a disposable culture, that we no longer take time to care.
The housewife is virtually obsolete; her role superseded by the ‘need’ to go out and earn money (in order to consume more of the stuff that will make her and her family happy) and money is the current currency of value in our world. Not the woman (or man) who can make 3 days meals from a couple of potatoes or grow their own stuff …
You won’t reduce food waste by better plastic packaging; you’ll reduce it by getting back to the root of the problem which is lack of understanding by householders and corrupt values in our society.
If we remember the ‘waste not want not’ mantra of the war and post-war ear, we won’t have this problem I’m sure and neither will there be the need for so much packaging.
Hi Mrs Green,
Most people like us would try to compost our tissues etc. I noticed a while ago that Coop tissues, in addition to wood pulp have a “wet strength additive”. Apparently most, if not all, products like this have these additives which are a form of resin. I phoned up the Coop’s freephone number to find out what this substance does when the tissue is composted and although I didn’t find out exactly what it breaks down to, they did say CO2, water and “biomass”.
I had been worried that it may not break down like the polyester in tea bags. Did you know about this? Just about all tea bags have a polyester additive in the paper so they can be heat sealed in manufacture. When they are composted they leave behind a faint polyester skeleton which is particularly obvious in wormeries where it can build up over a year or so to make almost impenetrable (for the worms) layers . I haven’t seen any other web site (even CAT - Centre for Alternative Technology) that is aware of this plastic contamination due to tea bags because they all recommend composting them. Since I found out, I tear the bag (when cooled) and tip the leaves into the compost and throw the bag into the bin.
Hi Nick,
Good to see you. I never knew about the tissues; but I did know about tea bags; how confusing. I’m going to look out for these tissues when I’m next in the Co-Op and see if I can find out more. Thanks for the heads up. The answer given to you wasn’t particularly helpful.
I think you are right to tear up the teabags if you are not sure. Perhaps it is time for a loose tea revolution!
Hi Mrs Green,
Basically, I suspect all facial tissues have these additives, almost certainly toilet tissue and kitchen towel roll too. I think it was just that the Co-ops environmental policy meant that they listed the additive in the ingredients - and that the other manufacturers don’t bother…
@Nick Palmer: Hi Nick; you know this is something I have simply never thought of before. So you think they might be in all products and because labelling laws are such a farce the manufacturers don’t have to mention it. It’s worth looking into isn’t it; to find out the facts.
I always feel good about the Co-ops transparency; to me they are one of the better supermarkets.
Fascinating stuff - thank you!
Hi Nick! I ADORE you!!
I’ve been wondering about the teabags for like, forever!
& the other tissues/paper towels etc too!
It would still be great to know about all teabags & tissues, & ideally making all manufacturers report all ingredients & processes (total transparency) would be best!!
/any efforts on this anywhere yet? Would TOTALLY sign that petition!!/
We don’t drink much tea in teabags, just the occasional few.. mostly just use herbal teas picked by family members or relatives.. Yeah you need a sieve, but it’s all fully compostable & no trash!
Mrs G, awesome investigation! It’s great you did follow up (as we can see what can happen..) & by now they also have more info than last year!
I agree with John that refillable systems would be better in the long run! If milk-o-mats exist & have proven successful, why not have other things refillable or in returnable packaging too?
you can buy beer from a refillable canister, poured into your glass, why not other stuff?
must think of any pertinent question - I may have some. Or have you written to them already?
How does lighter packaging reduce transport costs? Do the transport companies charge per kilo? I suspect packaging recovery companies may!) Is transport not calculated by volume? - I would REALLY like to know how they calculate this!
& no packaging surely is more lightweight than plastic packaging?
The highlighted parts - you’re gonna inquire about this, right?
PLA in small quantities on cardboard does not represent an issue for cartonboard recycling mills - Have you asked the mills directly too? It’s surprising what you get if you ask different people..
They also say to be using ‘Home Compostable’ stuff, & they say PLA doesn’t compost well at home-? now which is it? if they’re saying they’re staying away from just ‘degradable’ then good for them, indeed!
must say I’m partly impressed with their efforts, would still like to see some inconsistencies explained & improved.. ideally zero waste organizations & people would be talking to the packaging experts & decision makers in shops worldwide!!
& together better alternatives could be found..
Hi Layla, one thing about transportation costs is that if you run a car, it is said that reducing load, by taking things out of the boot for example, increases fuel economy.
@John Costigane:
I have successfully composted a few types of PLA products in my home compost pile: spoons from an ice cream shop, plates, and most recently, bowls from Annie Chun’s asian cuisine products. And definitely in less than 72 days.
With the proper proportions of green/brown matter and a heavy dose of sunlight, almost everything I put in breaks down in less than 3 months. Minus the big sticks and thick wood chunks. We compost approximately 1500 pounds of scraps from the kitchen every year.
If you set up the pile right, it’ll do it’s job.
The compost I get as a final product is invaluable. I have a neighbor that spends hundreds of dollars on special soil, fertilizer, amendments, watering systems, etc. for his tomatoes. He even grows them in pots to control the soil balance just where he wants it. I grow my tomatoes in my garden, with a six inch mix of half soil and half compost. If I have some laying around, I may sprinkle on some tomato food once. But that’s it.
My plants are healthier, put out twice the fruit, and are sweeter. Currently, my cherry tomato plants (Sweet 100s) are taller than me, and we have yet to pick one. He is jealous every year. Although this year they are so large I had to build another taller structure to keep them from crushing/tipping the tomato cages. Not a bad problem to have.
BTW…I am not a big fan of the microwave food products. But Annie Chun makes more that a few tasty soup and noodle dishes that I keep on hand. Partly because I like them, but mostly because I can recycle/compost 98% of the packaging.
http://www.anniechun.com
I have kept a half dozen of the soup bowls as my kids like the shape and size. They use them for morning cereal or movie night popcorn for a few months until they crack somewhere. Then into the compost with the rest of them.
@Chris Ramsay: Hi Chris, It is good to see some positive outcomes with PLA, though the material is not specifically designed for all types of composting, damp composting for example.
My view is that we should insist on low temperature composting material so that all home sites can use it. The Zero Waste perspective is to eliminate all single use plastic packaging (waste) and PLA does not meet the conditions for that.
I’ve only just ready this post today but I think it is a very interesting issue. I have been putting biodegradable plastic, teabags and tissues in my compost for the past year.
I usually do my supermarket shopping at Sainsbury’s, where the organic fruit and veg is wrapped in compostable plastic, which is made from maize, sugar cane or starch, and they say that it in tests it breaks down faster than a banana skin: http://www.j-sainsbury.com/cr/index.asp?pageid=69&year=archive§ion=3 However it does not say whether the tests were based on industrial or home composting, and in practice I have found large bits of this ‘plastic’ that have not broken down. However some bits have so I don’t know if it’s just my compost bin (it is in the shade and so it might not get hot enough). I’ve now started cutting them up to help speed up the process.
I also find that the teabags don’t break down as well unless I tear them open, but I have been putting the whole bag in. I use organic teabags - do you think that even they will have the polyester in? I did research whether teabags were ok to compost and everything I read said yes! Very frustrating.
The tissues so far seem to have broken down ok but who knows if there are some invisible molecules of something nasty lingering behind
The bowl from Annie Chun break down real nice. The “compostable” plates and bowl I have been buying break down, but the top layer seems to be a plastic or complete different material as it is still present even after a few months. It’s thin and easy to pick out. But I think I will switch brands.
@Zoe: If you compost tea bags in a standard garden compost heap you probably won’t notice the polyester “skeleton” because the food waste will be “diluted” by all the other stuff plants, cardboard etc. Also the turning process will “scrunch up” the remains of the tea bag. Wormeries make the problem obvious because they use concentrated food waste and tea bags tend to be a fair proportion of that. Plus the worms don’t “scrunch up” the bags, they just nibble the contents and the paper part of the bag and leave the polyester alone. I don’t know if organic tea bags are different - I suppose they still have to seal the bags somehow.
I am studying marketing at university and was wondering if anyone had the answer to my questions:
Can corn starch products be used for dairy products (in particular yoghurt pots) ?
What is the life expectancy of such packaging?
If kept refrigerated does it last longer?
Is it more expensive than standard polystyrene packaging (normal yoghurt pots) ?
I would be extremely grateful if anyone could post some answers or even better email me some replies
Adam - adam.bell@hotmail.com
@Adam Bell: Hello Adam, welcome to the site and good luck with your studies. I think your best bet would be to contact a plastics manufacturing company to ask these questions. Our focus is on helping householders reduce the amount of waste they send to landfill, and as such, our technical knowledge is limited.
You could try the American Plastics Council - I’m not sure who the UK equivalent would be.
Hmm.. Adam, I think it’s awesome you are studying and researching this!!
Like Mrs Green said, it would probably be best to ask around, manufacturers, chemists and elsewhere - not only for these questions, also for how really biodegradable and really eco they are: I wouldn’t trust the manufacturers or their scientists alone, on biodegradability issue it would maybe be good to contact Friends of the Earth or GAIA (Global Alliance Against Incinerators) and ask if they know any good independent scientists or studies..!!
I think it might depend on how it’s made, any additives etc. You could also ask about packaging made of diary by-products etc.
Personally I don’t trust ‘biodegradable’ plastics much, and it doesn’t really make sense to not biodegrade with yogurt in it.. Though if you google ‘biodegradable packaging yogurt’ quite some links pop up, so you might do some reading.. some stuff pops up if you add ‘corn starch’ to the mix, but I’m too busy to google right now
Wishing you to find out lots, and do tell us if you find anything exciting!