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Extending the shelf life of produce

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More than 30% of the world’s food is lost after it has been harvested.  That’s enough to feed more than a billion people.  Much of that loss is fruits and vegetables that go bad before they can be eaten.

Refrigeration is the most common way to preserve foods, but the energy and infrastructure required is not always available, especially in less affluent regions of the world.

Researchers at MIT and Singapore-based collaborators have demonstrated that they can extend the shelf life of harvested plants by injecting them with melatonin using biodegradable microneedles.

Silk microneedles are tiny, nontoxic, and biodegradable and represent a means of delivering nutrients to plants without triggering a stress response.

Melatonin is a natural hormone that plants already use.  Injecting it was shown to extend vegetables’ shelf life.  The tests used pak choy, an important Asian crop that is very perishable.  Untreated plants at room temperature yellowed within two or three days.  In contrast, treated plants stayed green for five days.  Overall, treated plants retained saleable value for 8 days.  Refrigerated plants had their shelf life extended considerably as well.  However, the most significant value of the technique is that it could enhance the shelf life of perishable produce like pak choy without needing access to refrigeration.

The dose of melatonin delivered to the plants is so low that it is fully metabolized by the crops, so it would not significantly increase the amount normally present in the food.  People would not ingest more melatonin than usual.  The researchers believe that their technique should work with all kinds of produce.

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A new technology for extending the shelf life of produce

Photo, posted May 6, 2010, courtesy of Jessica Spengler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Transparent wood

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Plastics are pretty much everywhere in the modern world including places we want them to be and places where we don’t.  Conventional plastics are not biodegradable and instead cause increasing problems wherever they end up after their useful life.  As a result, there are global efforts to find environmentally friendly replacements for petroleum-based plastics.

An interesting candidate for replacing many types of plastic is transparent wood.  Transparent wood is a man-made material derived from natural wood.  Wood has three components:  cellulose, hemicellulose, and lignin.  Transparent wood is created by removing the lignin and hemicellulose, leaving behind a porous, paper-like network of cellulose.  It is transparent but lacks structural strength.  In the past, clear materials like epoxies have been added to produce a strong, transparent material:  transparent wood.  But because of the epoxy – itself a form of plastic – the resultant material was non-biodegradable.

Researchers at Kennesaw State University in Georgia have developed a method for producing transparent wood that replaces epoxies with an egg white and rice extract mixture along with a curing agent called diethylenetriamine.  The end product is a semi-transparent form of wood that is biodegradable. 

The researchers also incorporated silver nanowires into samples of their transparent wood.  This enabled the wood to conduct electricity and could be useful in wearable sensors or as coatings for solar cells.  There is additional research needed to improve the properties of this transparent wood, but a plastic replacement made from natural and inexpensive materials could be quite valuable.

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Making sturdy, semi-transparent wood with cheap, natural materials

Photo, posted August 1, 2017, courtesy of NOAA Marine Debris via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Eliminating plastic shipping pillows

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Anyone who gets packages from Amazon is familiar with the plastic air pillows used to keep products safe in transit.  Amazon uses almost 15 billion of them a year in North America.

Environmentalists have been urging Amazon and other vendors to cut down on the use of plastic packaging. The air-filled plastic pillows are made from plastic film, which is the most common form of plastic litter found in the sea and in seabeds along the shore.  Plastic film can be deadly to wildlife such as sea turtles and sea birds.  Plastic film generally can’t be composted or recycled either.

Recently, Amazon announced that it will replace its plastic pillows with recycled paper filler in all its North American markets – the United States, Canada, and Mexico – which together account for more than 70% of the retailer’s global sales.  It is already making the switch in a big way and is working towards fully removing the plastic materials by the end of the year.

Replacing plastic packaging with paper is a definite improvement.  Paper is recyclable and biodegradable.  It isn’t perfect:  if it ends up in landfills, it can contribute to methane pollution as it biodegrades.  But, on the other hand, paper packaging is more likely to be recycled.

Stemming the tide of plastic waste is an ongoing effort by environmental and consumer groups.  There is pending legislation in New York that aims to reduce the use of plastic packaging by 50% over 12 years by requiring manufacturers to either replace it or pay fees.  The bill cleared the State Senate but has not come up to a vote in the Assembly.  Similar legislation has already been passed in California, Oregon, Maine, and Colorado.

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Amazon Says It Will Stop Using Puffy Plastic Shipping Pillows

Photo, posted November 20, 2018, courtesy of Todd Van Hoosear via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Biodegradable microplastics

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Ordinary plastics are not biodegradable, but they are also not indestructible.  Plastics in the environment can break down into tiny fragments – microplastics – and those, unfortunately, are nearly indestructible.  Microplastics have been documented in the oceans and in soil virtually everywhere on Earth including remote frozen wastelands and on top of high mountains.  More recently, they have been found in our own arteries, lungs, and even in placentas.  Microplastic pollution is a very serious problem.

There is considerable ongoing effort to develop biodegradable plastics from non-petroleum sources.  There has been progress but it has not necessarily been aimed at creating bioplastics that do not create microplastic when they break down.

Researchers at the University of California San Diego have developed algae-based polymers that they have shown to degrade when composted.  Recently, in work published in the journal Nature Scientific Reports, they have shown that even fine microparticles of their bioplastic are digested by microbes when placed in a compost.  What remains are the starting plant materials from which the plastic was made.  Products made from this sort of plastic would not only be sustainable beyond their useful lifetime but would also not represent a potential danger to human life.

Creating this eco-friendly alternative to petroleum-based plastic is only the first step toward creating a viable replacement for existing plastics.  It is necessary to be able to use the new material on existing manufacturing equipment and for it to have the same mechanical and thermal properties as the materials it is replacing.  But the researchers are optimistic that this could be a potential solution to an increasingly serious problem.

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Say Hello to Biodegradable Microplastics

Photo, posted January 17, 2018, courtesy of Bo Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastics and agriculture 

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Once celebrated as a symbol of modern innovation, plastic is now both a blessing and a curse of our time.  Since the 1950s, more than nine billion tons of plastic have been produced, and 50% of that has been during the past 15 years.  Plastic is ubiquitous in every sector, and agriculture is no different.

Modern agriculture is responsible for almost a third of global greenhouse gas emissions and is a major drain on the planet’s resources.  Modern agriculture is also inextricably linked to plastic. In fact, more than 13 million tons of plastic are used in agriculture every year.  It’s nearly impossible to imagine modern agriculture without plastics. 

But according to a new study led by researchers from Rutgers University, plastic use in agriculture must be reduced in order to mitigate pollution, and prevent toxic chemicals from leaching into the soil and adversely affecting human health. 

In the study, which was recently published in Nature Communications Earth & Environment, the researchers found that it is essential to adopt a strategic approach to mitigate plastic pollution in agriculture, including responsible usage, reduction, efficient collection, reuse, and the implementation of innovative recycling methods. 

According to the researchers, when these sustainable approaches aren’t possible, biodegradable and nontoxic bioplastics should be used.  The research team insists that environmentally benign additives should be mandated in order to reduce plastic toxicity. 

Plastic pollution is a problem that needs to be addressed in every sector. 

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Plastic Use in Agriculture Must be Reduced, According to New Research

How can the use of plastics in agriculture become more sustainable?

Photo, posted November 12, 2022, courtesy of Kevin Dooley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Computing With Honey | Earth Wise           

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Researchers are always working to develop faster and more powerful computers.  Some of them believe that the future of computing lies with neuromorphic computers, which are systems designed to mimic the neurons and synapses found in the human brain.

The human brain has more than 100 billion neurons with more than 1 quadrillion synapses or connections among them.  These numbers far exceed anything people have built.  There have been some neuromorphic computer chips made that have the equivalent of more than 100 million neurons per chip, but this is still far less than the number in the brain.  Despite all its complexity, the brain uses vastly less power than a powerful computer.  Some supercomputers use tens of millions of watts to operate; the brain uses around 10 to 20 watts.

Many researchers are searching for biodegradable and renewable ways to make neuromorphic computing components.  Researchers at Washington State University have demonstrated a way to make them using, of all things, honey.  The honey is used to form a memristor, which is a component similar to a transistor that can both process and store data in memory.  The device uses honey processed into a solid form and sandwiched between two metal electrodes.  The organic device is very stable and reliable over a long time.

So far, these devices are on a micro scale – about the size of a human hair.  The researchers want to develop them on a nanoscale, which is about 1/1000 the width of a human hair, and then bundle many millions or even billions together to make a neuromorphic computing system.  Such a honey-based system would be renewable and biodegradable – which, pardon the pun, would be really sweet.

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Honey holds potential for making brain-like computer chips

Photo, posted January 28, 2008, courtesy of Dino Giordano via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Better Ways To Make Bioplastics | Earth Wise

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The world produces over 300 million tons of plastics each year, mostly produced from petroleum.  The environmental consequences are substantial and there is a critical need to replace as much of that plastic production with biodegradable plastics as possible.  Thus, there is global research aimed at making bioplastics more economical and as environmentally friendly as possible.

Researchers at Texas A&M University have developed an improved approach for making bioplastics from corn stubble, grasses, and mesquite agricultural production.  Apart from the obvious environmental benefits of having biodegradable plastics, producing bioplastics from common agricultural waste would create new revenue streams for farmers as well as the people who transport harvested feedstock and byproduct crops to refinery operations.

The key to bioplastic production is the efficient extraction and use of lignin, the organic polymer that is the primary structural support material in most plants.  The new research takes five conventional pretreatment technologies for plant materials and modifies them to produce both biofuel and plastics together at a lower cost.  The new method is called “plug-in preconditioning processes of lignin” and it can be directly and economically added into current biorefineries.  The process is designed to integrate dissolving, conditioning, and fermenting lignin, extracting energy from it and making it easily adaptable to biorefinery designs.

The so-called bioeconomy currently supports some 286,000 jobs.  Innovation is the key to achieving more widespread use of biodegradable plastic.  With improved economics of so-called lignocellulosic biorefineries, there can be new avenues to use agricultural waste to produce biodegradable plastics.

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‘Plugging in’ to produce environmentally friendly bioplastics

Photo, posted November 5, 2015, courtesy of Kathryn Faith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Seeds And Climate Change | Earth Wise

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Farmers and agricultural communities around the world are on the frontlines of climate change.  They are among the first to feel the impacts of hotter temperatures as well as more frequent and intense droughts and precipitation. These challenges pose a massive threat to both farmer livelihoods and global food security.

As the planet continues to heat up, many arid regions that already have marginal conditions for agriculture will be increasingly under stress. As a result, researchers from the Massachusetts Institute of Technology and the King Mohammed VI Polytechnic University in Morocco are working on a promising new way to protect seeds from this stress during their crucial germination phase. Their simple and inexpensive process, which was recently described in a paper published in the journal Nature Food, also provides plants with extra nutrition at the same.

The research team has developed a two layer coating for seeds designed for tackling issues related to drought. Drawing inspiration from natural coatings that occur on some seeds like chia seeds, the first layer is designed to protect the seeds from drying out. It provides a gel-like coating that grips any moisture that comes along and surrounds the seed with it.  The second (inner) layer of the coating contains preserved microorganisms called rhizobacteria, as well as some nutrients to help the seeds grow. 

The materials for the coatings are biodegradable, readily-available, and often used in the food industry already.  According to researchers, early tests using common beans have demonstrated encouraging results in Morocco, and more field tests of the seeds are currently underway.

As the climate continues to change, more innovations like this will be necessary for global food security.

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Engineering seeds to resist drought

Photo, posted September 17, 2010, courtesy of Stacy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Takeout Food And Ocean Litter | Earth Wise

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The Covid-19 pandemic saw most of us making use of take-out or delivery services as our only access to restaurant food.  It was a valuable link to normal life.  But unfortunately, the packaging of takeout food is a major contributor to the global plastic waste problem that isn’t going to disappear just because people are returning to eating in restaurants.

A new analysis of more than 12 million items by UK researchers published in the journal Nature Sustainability has found that the majority of ocean litter collected around the world is in the form of takeout food items:  bags, wrappers, containers, straws and cutlery, aluminum cans, and plastic and glass bottles.  Eighty percent of all the items surveyed were made of plastic.

Wrappers and packaging tended to concentrate along coasts, gathering on the shore and the sea floor.  Takeout trash was rarer in the open ocean.  In those areas, fishing debris accounted for half of the litter.

The authors of the study argue that efforts to curb plastic waste should prioritize takeout food and beverage containers.  They recommend that avoidable takeout items, like single-use plastic bags, should be replaced with non-plastic and biodegradable materials.  The authors also recommended making plastic producers responsible for the collection and disposal of plastic products.

As of July 1, the European Union has banned the 10 most common plastic and Stryofoam products found on European beaches.  The EU is also establishing an active European market for recycled plastics based on the principles of extended producer responsibility.

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Takeout Food and Drink Containers Account for Bulk of Ocean Litter

Photo, posted September 14, 2009, courtesy of Susan White/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning Wood Into Plastic | Earth Wise

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Plastic pollution is particularly pernicious because plastics can take hundreds of years to degrade in the environment.  For this reason, researchers across the globe search for ways to shift from petrochemical plastics to ones that are biodegradable.

Producing biodegradable plastics is challenging both from the standpoint of the methods needed and from the results obtained.  Producing them often requires toxic chemicals and can be very expensive.  The materials that emerge often do not have the durability and strength of conventional plastics and can be unstable when exposed to moisture.

Researchers at the Yale School of the Environment have developed a process of decomposing the porous matrix of natural wood into a slurry that can be formed into a biodegradable plastic.  The material shows high mechanical strength, stability when holding liquids, and is resistant to the effects of ultraviolet light.  Along with all these favorable properties, the material can be recycled or safely biodegraded in the natural environment.

The slurry mixture is created by taking wood powder – a processing residue usually discarded in lumber mills – and deconstructing it with a biodegradable and recyclable solvent.  The resulting mixture has a high solid content and high viscosity and can be casted and rolled without breaking.

The researchers conducted a comprehensive life cycle assessment to test the environmental impacts of the bioplastic compared with conventional plastics.  Sheets of it were buried in soil and observed to fracture after two weeks and completely degrade after three months.  The material can also be broken back down into the slurry by mechanical stirring.

The remaining topic to investigate is the potential impact on forests if the manufacturing of this bioplastic is scaled up.

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Turning wood into plastic

Photo, posted October 12, 2016, courtesy of the US Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Food Waste Into Wearables | Earth Wise

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A new startup company spun out of the University of Toronto wants to make clothing from food waste.  If they are successful, you may someday buy a shirt or a pair of gym shorts made from banana peels, rotten tomatoes, coffee grounds, or moldy bread.

A problem faced by the clothing industry is that most textiles are blended with synthetic and non-renewable fiber polyester, which makes them unrecyclable.  An alternative that has come on the scene in recent years is polylactic acid (or PLA), which is a decomposable bioplastic that is currently used for food packaging, medical implants, and 3D printing.  It is likely that a sustainable future for the fashion industry will depend on the ability to make use of biodegradable and carbon-neutral materials.

PLA is typically made from cornstalk, but the startup – called ALT TEX – does not want to rely on a crop already used for feedstock, human consumption, and alternative fuel.  Furthermore, there is no need to plant more corn when there is an abundant supply of unused post-industrial food waste from growers, producers, and retailers that contains the same biological building blocks for producing PLA.

ALT TEX has been conducting experiments using discarded apples to create a PLA-based fabric that is strong, durable, decomposable, and cost effective.  They are working with farmers and food suppliers to access their waste. If their efforts are successful, it would be possible to divert significant amounts of organic waste that currently emits the powerful greenhouse gas methane and instead enable the fashion industry to be more sustainable.

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Earth-friendly fashion: U of T startup turns food waste into wearables

Photo, posted August 30, 2019, courtesy of Ruth Hartnup via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Plants Paying For Biofuels | Earth Wise

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Biofuels are an important element in broader strategies to replace petroleum in transportation fuels like gasoline, diesel, and jet fuel.  The idea is that biofuels recycle carbon by getting it from growing plants rather than from fossil sources.  The biggest problem with biofuels is that they cost more than conventional petroleum fuels, so there is economic incentive to keep burning the fossil fuels.

One strategy to make biofuels cost competitive is to have the plants provide additional economic benefits beyond being a feedstock for fuel.  This in principle can be done by engineering plants to produce valuable chemical compounds, or bioproducts, as they grow.  Bioproducts include such things as flavoring agents and fragrances as well as biodegradable plastic.  These bioproducts can be extracted from the plants and then the remaining plant material can be converted to fuel. 

Researchers at Lawrence Berkeley National Laboratory recently published a study to determine what quantities of bioproducts plants need to produce to result in cost-effective biofuel production.

The study looked at a compound called limonene, which is used for flavoring and fragrance.  They calculated that if this compound was accumulated at 0.6% of the biomass dry weight, it would offer net economic benefits to biorefineries.  This corresponds to recovering 130 pounds of limonene from 10 tons of sorghum on an acre of land.

Such quantities are completely practical but, on the other hand, none of these substances are needed in huge quantities. Just six refineries could supply the world with limonene.  So, fuel crops would need to be engineered to produce a broad range of bioproducts to enable a viable cost-effective biofuel industry.

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Making Biofuels Cheaper by Putting Plants to Work

Photo, posted September 28, 2019, courtesy of Michele Dorsey Walfred via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sustainable Plastics

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According to the United Nations, plastic accounts for up to 90% of all the pollutants in the ocean. Conventional plastics take hundreds of years to decay, so all the plastic that gets into the oceans piles up and endangers marine life and pollutes the environment. Unfortunately, there are few comparable, environmentally friendly alternatives.  

An often-proposed solution is bioplastics, which are not made from petroleum and degrade quickly.  The downside of bioplastics is that growing the plants or bacteria used to make the plastic requires fertile soil and fresh water, which are scarce commodities in many places.

One such place is Israel.  So, researchers there at Tel Aviv University have developed a process to make a bioplastic polymer that doesn’t require land or fresh water.  The new polymer is derived from microorganisms that feed on seaweed.  It is biodegradable, produces zero toxic waste and recycles into organic waste.

The polymer is called polyhydroxyalkanoate, or PHA for short.  The raw material is multicellular seaweed, cultivated in the ocean.  These algae are eaten by single-celled microorganisms, which also grow in salty seawater and produce a polymer that can be used to make bioplastic.  PHA is already produced in commercial quantities, but it is currently made from plants that require agricultural land and fresh water.  The new process would enable countries with limited fresh water, such as Israel, China and India, to switch from petroleum-based plastics to biodegradable plastics.

Plastics from fossil sources are one of the world’s biggest pollution problems.  The new study shows that it is possible to produce bioplastic completely based on marine resources in an environmentally-friendly process. 

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Sustainable ‘plastics’ are on the horizon

Photo, posted March 14, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Car Parts From Agricultural Waste

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A new bio-composite material made from date palm fiber biomass could be used to produce sustainable, lightweight and low-cost parts for the automobile and marine industries.

A team of researchers from the UK has developed a date palm fiber polycaprolactone composite that is completely biodegradable, renewable,sustainable and recyclable, in contrast to synthetic composite materials reinforced by glass and carbon fibers. The team tested the mechanical properties of the material and found that it achieved better low-velocity impact resistance than traditional man-made composites.

The idea would be to use the material in non-structural auto parts such as car bumpers and door linings.   The result would be to reduce the weight of vehicles, contributing to less fuel consumption and lower emissions.  The new material can be produced using less energy than glass and carbon fibers and is biodegradable and therefore easier to recycle.

Date palm fibers are one of the most available natural fibers in many parts of the world.  The trees produce a large quantity of agricultural waste, which is mostly burned or land-filled,causing serious environmental problems.

Convincing industry to use a new class of materials such as natural-fiber reinforced composites is challenging.  First it is necessary to obtain consistent,reliable properties from the material. Then the industries need to work closely with the developers to test the materials and convince themselves of the viability of using them.  The team, led by researchers at the University of Portsmouth, has been working with industry to test the viability of parts made from a variety of other sustainable materials as well including flax, hemp, and jute.  Someday, our cars may have bumpers made from agricultural waste.

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Agricultural waste drives us closer to greener transport

Photo, posted October 27, 2017, courtesy of David Stanley via Flickr. 

Earth Wise is a production of WAMC Northeast Public Radio.

Mass Production Of Biodegradable Plastic  

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Plastic pollution is a major problem for the world’s oceans and non-biodegradable plastics continue to fill the planet’s landfills and litter the landscape.   There are many approaches to making plant-derived, biodegradable plastics but most of these materials do not offer the resistance to heat and moisture that is characteristic of petroleum-based plastics.

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Biodegradable Microbeads

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Microbeads are little spheres of plastic less than half a millimeter in diameter that are added to a variety of personal care and cleaning products such as cosmetics, sunscreens and fillers.  They give these products a desirable smooth texture.   However, they are so small that sewage filtration systems can’t remove them and they end up in rivers and oceans where they are ingested by birds, fish and other marine life.

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Edible Tableware

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The problems caused by plastics in the environment continue to mount.  Major companies around the world are endorsing and promoting efforts to combat the problem including the New Plastics Economy Initiative which aims to have 70% of plastic packaging reused and recycled globally, which is five times more than the current percentage.

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