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Extending the shelf life of produce

July 10, 2025 By EarthWise Leave a Comment

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

Removing nanoplastics from water

September 26, 2024 By EarthWise Leave a Comment

Plastic pollution is a growing problem for people and for the environment in multiple ways. When plastics break down over time, they can form small particles called microplastics – bits smaller than sesame seeds – and these, in turn, can break down into even smaller pieces called nanoplastics. They are too small to be seen with the naked eye and can enter the body’s cells and tissues.

Recent studies have shown that nanoplastics are increasingly showing up in bottled water. In fact, measurements on several popular brands of bottled water found an average of nearly a quarter million tiny pieces of plastic in a single liter of bottled water.

The health effects of ingesting all of this plastic are not really known, but they are unlikely to be anything good. Finding a way of avoiding this contamination of the beverages we drink is a pressing need.

Researchers at the University of Missouri have created a new liquid-based solution that eliminates more than 98% of microscopic plastic particles from water. The method makes use of water-repelling solvents made from safe, non-toxic natural ingredients. A small amount of this designer solvent absorbs plastic particles from a large volume of water.

The solvent sits on the water’s surface. When mixed with the water, it absorbs the plastic and eventually comes back to the surface carrying the plastic leaving behind clean, plastic -free water.

Ultimately, the hope is to scale up the process so it can be applied to increasingly large amounts of water – even lakes and, eventually, oceans. There is work to be done, but it is a potential way to address an increasingly worrisome and pervasive form of pollution.

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Mizzou scientists achieve more than 98% efficiency removing nanoplastics from water

Photo, posted August 9, 2012, courtesy of Enid Martindale via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Balloon release laws

May 27, 2024 By EarthWise Leave a Comment

The Florida state legislature has recently passed a law that bans the intentional release of helium balloons outdoors. It is a rare example of a bipartisan piece of legislation. Florida is joining six other states that have already enacted balloon restricting laws.

Balloons released into the sky don’t just disappear into the ether. They often end up in oceans and waterways and the thin material that remains is 32 times more likely to kill seabirds than other types of plastic debris. Aquatic animals often mistake balloons for jellyfish and fill up on them. Balloons tied up with ribbons entangle turtles and manatees. Even grazing cows have died from ingesting balloons. Balloons contribute to microplastic pollution, which is a growing problem for all living things, including humans.

Other states with balloon release laws are Connecticut, Tennessee, New York, Texas, California, and Virginia. Details of the laws vary. They carve out exceptions for specific applications. They exempt small children. Some limit the quantity of balloon release. Others require balloons to be weighted down to prevent them from rising too high. California’s legislation is aimed at the metallized mylar balloons that have shorted out high-tension electrical wires and triggered wildfires.

The Florida law equates intentionally releasing a lighter-than-air balloon with littering. It’s a non-criminal offense that carries a fine of $150.

People enjoy releasing helium balloons, particularly en masse. The spectacle has become part of weddings, gender reveal parties, and even funerals. But the practice has serious environmental repercussions, and its restriction is being pursued by more and more states and municipalities.

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Up, Up and Not OK: Letting Go of Balloons Could Soon Be Illegal in Florida

Photo, posted August 16, 2022, courtesy of Ryan Mandelbaum via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio