Three oranges in a row on a blue background, the center orange is moldy
It’s a home cook’s nightmare: You open the fridge ready to make dinner and realize the meat has spoiled. You have to throw it out, kicking yourself for not cooking it sooner.
According to the USDA, a staggering one-third of food is tossed out because of spoilage, leading to over $160 billion lost every year. Much of this food is protein and fresh produce, which could feed families in need. The land, water, labor, energy, and transportation that brought the food to people’s homes also goes to waste.
Canada’s McMaster University has a solution. A team of scientists wrapped virus-packed microneedles inside a paper towel-like square sitting at the bottom of a Ziploc container. It’s an unusual duo. But the viruses, called phages, specifically target bacteria related to food spoilage. Some are already approved for consumption.
Using microneedles to inject the phages into foods, the team decontaminated chicken, shrimp, peppers, and cheese. All it took was placing the square on the bottom of a storage dish or on the surface of the food. Mixing and matching the phages destroyed multiple dangerous bacterial strains. In some cases, it made spoiled meat safe to eat again based on current regulations.
It’s just a prototype, but a similar design could one day be used in food packaging.
“[The platform] can revolutionize current food contamination practices, preventing foodborne illness and waste through the active decontamination of food products,” wrote the team.
A Curious Food Chain
It’s easy to take food safety for granted. The occasional bad bite of leftover pizza might give you some discomfort, but you bounce back. Still, foodborne pathogens result in hundreds of millions of cases and tens of thousands of deaths every year according to the World Health Organization. Bacteria like E. Coliand Salmonella are the main culprits.
Existing solutions rely on antibiotics. But they come with baggage. Flooding agriculture with these drugs contributes to antibacterial resistance, impacting the farming industry and healthcare.
Other preservative additives—like those in off-the-shelf foods—incorporate chemicals, essential oils, and other molecules. Although these are wallet-friendly and safe to eat, they often change core aspects of food like texture and flavor (canned salsa never tastes as great as the fresh stuff).
Maverick food scientists have been exploring an alternative way to combat food spoilage—phages. Adding a bath of viruses to a bacteria-infected stew is hardly an obvious food safety strategy, but it stems from research into antibacterial resistance.
Phages are viruses that only infect bacteria. They look a bit like spiders. Their heads house genetic material, while their legs grab onto bacteria. Once attached, phages inject their DNA into the bacteria and force their hosts to reproduce more viruses—before destroying them.
Because phages don’t infect human cells, they can be antibacterial treatments and even gene therapies. And they’re already part of our food production system. FDA-approved ListShield, for example, reduces Listeria in produce, smoked salmon, and frozen foods. PhageGuard S, approved in the US and EU, fights off Salmonella. Other phage-based products include sprays, edible films, and hydrogel-based packaging used to decontaminate food surfaces.
Even better, phages self-renew. They are “self-dosing antimicrobial additives,” wrote the team.
But size has been a limiting factor: They’re too big. Phages struggle to tunnel into larger pieces of food—say, a plump chicken breast. Although they might swiftly wipe out bacteria on the surface, pathogens can still silently brew inside a cutlet.
Prickly Patch
The new device was inspired by medical microneedle patches. These look like Band-Aids, but loaded inside are medications that can seep deeper into tissues—or in this case, food.
To construct food-safe microneedles, the team tested a range of edible materials and homed in on four ingredients. These included gelatin, the squishy protein-rich component at the heart of Jell-O, and other biocompatible materials readily used in medical devices. The ingredients were poured into a mold, baked into separate microneedle patches, and checked for integrity.
Each ingredient had strengths and weakness. But after testing the patches on various foods—mushrooms, fish, cooked chicken, and cheese—one component stood out for its reusability and ability to penetrate deeper. Called PMMA, the coating is already used in food-safe plexiglass and reusable packaging.
The team next loaded multiple phages that target different food-spoiling bacteria into PMMA scaffolds and challenged the patches to neutralize bacterial “lawns.” True to their name, these are fuzzy microscopic bits of bacteria that form a carpet. You’ve probably seen them at the bottom of a food container you’ve left far too long in the fridge.
The phage patches completely erased both E. Coli and Salmonellain steaks with high levels of the bacteria. Another test pitted the patches against existing methods in leftover chicken that had lingered 18 hours in unsafe food conditions. Compared to directly injecting phages or applying phage sprays, the microneedle patch was the only strategy that kept the chicken safe to eat according to current regulations.
Phage Buffet
The system was especially resilient to temperature changes. When applied to chicken or raw beef, the phage patches were active for at least a month at regular refrigerator temperatures, “ensuring compatibility with food products that require prolonged storage,” wrote the team.
The system can be tailored to tackle different bacteria, especially by mixing up which phages are included. Using a variety could potentially target strains of bacteria throughout the food production line, making the final product safer.
The team is planning to integrate the platform into food packaging materials, which would ensure the microneedles are in constant contact with the food and deliver a large dose of phages that self-replicate to continue warding off bacteria. Other ideas include sprinkling phage-loaded materials directly onto food during manufacturing and production.
The idea of eating viruses might seem a little weird. But phages naturally occur in almost all foods, including meat, dairy, and vegetables. You’ve likely already eaten these bacteria-fighting warriors at some point as they’re silently hunting down disease-causing bacteria.
The vaccine could prevent foodborne illness and reduce waste. It’s easy to adapt to different strains of bacteria, food-safe, and cost effective, wrote the team, making it “well suited for applications within the food industry.”
Shelly Fan
Dr. Shelly Xuelai Fan is a neuroscientist-turned-science-writer. She's fascinated with research about the brain, AI, longevity, biotech, and especially their intersection. As a digital nomad, she enjoys exploring new cultures, local foods, and the great outdoors.
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