Protecting families from contaminated food and water
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Protecting families from contaminated food and water
Posted in Our Blog on June 27, 2026
Shelf life is a serious concern when it comes to perishable produce. The amount of waste is astonishing!
More than 30% of the world’s food expires before it is eaten. That adds up to enough food to feed 1.6 billion people.
Singapore scientists have discovered a novel solution to this growing problem.
Recent studies have shown successful extension of shelf life post-harvest by injecting plants with melatonin using biodegradable needles.
It is exactly as crazy as it sounds. But if it is successfully implemented, it could be a huge win in the fight to end world hunger.
But are there side-effects?
Here’s what we know so far about increasing the shelf life of produce with melatonin.
Researchers from MIT and Singapore-MIT Alliance for Research and Technology (SMART) have successfully increased the shelf life of produce using a never before used technique.
Microneedle injections of melatonin into inner tissues of plants.
Silk microneedles were selected for this project because they are strong enough to penetrate the tough, waxy skin of plants, yet do not cause a stress response. This method delivers “precise amounts of melatonin into plants’ inner tissues.”
They are made from silk fibroin protein and are safe for the environment. Silk microneedles are nontoxic and biodegradable and can be manufactured quickly in large numbers.
The lab has been working with this application technology for years. Other studies using these microneedles include delivering nutrients to crops and monitoring plant health.
“This is the first time that we’ve been able to apply these microneedles to extend the shelf life of a fresh-cut crop,” says Menedetto Marelli, the study’s senior author, associate professor of civil and environmental engineering at MIT, and the director of the Wild Cards mission of the MIT Climate Project. “We thought we could use this technology to deliver something that could regulate or control the plant’s post-harvest physiology.”
Melatonin is used in human hormonal regulation. Often as a sleep aid.
But plants?
What is the connection between melatonin and plants.
As it turns out, melatonin is produced and used by plants to reduce stress and slow the aging process.
How about that! You learn something new every day!
“We thought we could use this [silk microneedle] technology to deliver something that could regulate or control the plant’s post-harvest physiology. Eventually, we looked at hormones, and melatonin is already used by plants to regulate such functions,” said Marelli.
Melatonin has been detected in algae, bacteria, fungi, and plant families. Even in higher concentrations that what is typically found in animal blood.
To test the effectiveness of silk microneedle application of melatonin on produce shelf life, scientist designed a study around pak choy. A leafy vegetable chosen for its importance in Asia as well as its extremely perishable nature.
First, scientists wanted to be sure that an injection would make it though all parts of the plant.
To do this, they injected a fluorescent dye into the base of the plant where the vegetable was cut at harvest. They confirmed that the vasculature of the plant would spread the dye throughout the whole system.
To determine if a simpler methodology could achieve the same results as microneedle injections, researchers sprayed and dipped plants into melatonin.
They found no difference between the shelf life of untreated control pak choy plants with those where melatonin was applied to the surface.
This established a shelf life baseline for future comparison.
Finally, researchers applied small patches of melatonin-filled microneedles to the bottom of pak choy plants by hand.
Control plants were stored alongside treated plants in plastic boxes at both room temperature and under refrigeration conditions.
Scientists monitored the plant’s weight, visual appearance, and chlorophyll concentration (a pigment that decreases with age).
The results showed promising outcomes
Under room temperature conditions, the untreated control group showed yellowing within two or three days. By day four, plants were too far gone to sell.
Melatonin-treated plants, on the other hand, were still green on day five. “The yellowing process was significantly delayed.” Overall, researchers estimated that treated plants retained “saleable value” until the eighth day. Significantly increasing the room temperature shelf life of pak choy.
“We clearly saw we could enhance the shelf life of pak choy without the cold chain,” Marelli says.
Plants tested under refrigerated conditions were stored at around 40° F.
Untreated plants experienced a delay from plant yellowing of an average of five days.
Treated plants remained “relatively green” until day 25. A significant increase in shelf life!
Scientists already knew that melatonin was used by the plant to reduce stress. Their observations further proved this phenomenon.
“Spectrophotometric analysis of the plants indicated the treated plants had higher antioxidant activity, while gene analysis showed that melatonin set off a protective chain reaction inside the plants, preserving chlorophyll and adjusting hormones to slow senescence,” says Monika Jangir, co-first author and former postdoc at the Temasek Life Sciences Laboratory.
Melatonin reduces plant stress, and effectively increases shelf life.
And now for the million dollar question.
Is it safe?
Marelli says, “The dose of melatonin we’re delivering is so low that it’s fully metabolized by the crops, so it would not significantly increase the amount of melatonin normally present in food; we would not ingest more melatonin than usual.”
In fact, some studies indicate that plants high in melatonin can even be beneficial to humans.
One study indicated that “people have consumed these plants [high in melatonin] for their antioxidant, immunomodulator, anti-inflammatory, and anticancer effects.”
We consume plants and products made from them every day with naturally high amounts of melatonin.
Tea, coffee, beer, and wine, for example, all contain melatonin. All believed to have inherent benefits.
Coffee has shown to “decrease human prostate cancer”. Wine has “protective effect against heart injury.” Certain Chinese medicinal herbs are high in melatonin. The list goes on and on.
Even if it works. And it does not have a negative impact on consumers. Will farmers and producers use this technology?
While it does minimize waste, and therefore increase productivity, it may take some convincing to see this process become mainstream.
Researchers indicate that “patches could be applied using tractors, autonomous drones, and other farming equipment in the future.” Though, for this to be widely adopted, we’d need to reach a performance versus cost threshold to justify its use.”
Essentially, it needs to be cost-effective and cheap enough for farmers to use it regularly.
How do you feel about microneedle-injected melatonin in the food supply?
If you’d like to know more about food safety topics in the news, like “Scientists Discover New Way to Extend Shelf Life of Produce. You Won’t Believe How!,” check out the Make Food Safe Blog. We regularly update trending topics, foodborne infections in the news, recalls, and more! Stay tuned for quality information to help keep your family safe, while The Lange Law Firm, PLLC strives to Make Food Safe!
By: Heather Van Tassell (contributing writer, non-lawyer)