Imagine opening your fridge and finding spinach that still looks bright and crisp a full four days longer than usual. That future might be closer than you think, thanks to researchers at McGill University in Montreal.
They've discovered that shining low-intensity green LED lights on leafy greens while they chill in the fridge can significantly slow spoilage. The findings, published in the Journal of Food Science, could eventually help reduce the enormous amount of produce that gets tossed out simply because it looks wilted or faded.
The study focused on spinach and lettuce stored at 4 degrees Celsius — that standard refrigerator temperature. The team tested different lighting conditions: complete darkness, white light, and green LED light at two specific wavelengths. Green light won out.
"We found that something as simple as changing the light in refrigerated storage may help fresh produce stay fresher for longer," said Shafieh Salehinia, the lead researcher who worked on the project at McGill's Biomass Production Lab, led by Professor Mark Lefsrud.
The results were striking. Green LEDs helped the leaves hold onto moisture, which kept them from shriveling and losing their vibrant color. The light also preserved texture and helped maintain beneficial nutrients like antioxidants and anthocyanins — the compounds that give spinach its deep green and red hues. After 18 days of storage, the green-lit spinach still looked acceptable, compared to spinach stored in darkness, which showed visible decline earlier.
For home cooks, that could mean less food going bad in the crisper drawer. For grocery stores and farmers, it could mean fewer losses and a more sustainable supply chain.
The research fills a gap in existing science. Scientists have studied how red and blue light affects growing plants, but green light has largely been overlooked when it comes to keeping harvested vegetables fresh.
"Green light has often been overlooked in post-harvest research," Salehinia noted, "while red and blue light have received much more attention because of their known effects on plant growth."
The team has already patented the technology. Since green LEDs are inexpensive and widely available, scaling up the approach could be relatively straightforward — no fancy equipment required.
Of course, more work needs to happen before you'll see green-lit refrigerators at the grocery store. But the early results suggest a simple, low-cost fix could go a long way toward keeping produce on plates instead of in the trash.