Six hundred million people a year are affected by food poisoning. E. coli, Salmonella, ListeriaBacteria thrive in undercooked meat and processed foods. Bacteriophage sprays already exist, but they have a limitation: they only work on the surface. The bacteria hiding inside remain unharmed. Now a Canadian team has solved the problem with a simple yet effective solution: microneedles that penetrate food and release killer viruses exactly where they're needed. Tests on raw beef and cooked chicken eliminated 99,9% of the bacteria. E. coli. Nice shot!
How bacteriophage-laden microneedles work
The patch is placed on the surface of the meat. The whole process takes a few seconds. microneedles They penetrate, release their cargo, and retreat. Inside, millions of bacteriophages begin their hunt. They find E. coli, they attach themselves, inject their own DNA and explode it from the inside. The study published in Science Advances Document every step. In just a few hours, 99,9% of bacteria are eliminated. No antibiotics, no sprays that slide off the surface. Just viruses that hunt for bacteria with sniper precision.
Each needle is as thin as a sewing thread and just two millimeters long. The doctoral student Akansha Prasad of McMaster University He reasoned that if the microneedles worked at penetrating the human skin barrier, they might also work for food. He tested the patch on vacuum-packed cheese, mushrooms, peaches, and even that reddish liquid that drips from raw chicken. It worked everywhere.
The problem of surface sprays
I bacteriophages They are viruses that eat bacteria. Harmless to humans, lethal to E. coli e Salmonella. As I told you in this article about bacteria in microwavesMicroorganisms thrive in unexpected places. For years, they have been used in sprays to decontaminate food surfaces, but with limited success: the protein molecules of viruses are too large to pass through the three-dimensional structure of food. They remain outside while bacteria thrive inside.
La FDA approved spray with phage cocktail against Listeria monocytogenes e Salmonella Typhimurium. But according to WHO Europe (May 2025), effectiveness remains limited by surface penetration. The bacteria that matter, those hidden deep down, survive.
The numbers that count: 99,9% of E. coli eliminated
On raw beef contaminated with E. coli, microneedles They achieved a reduction of 3,4 logs. That means 99,9% of bacteria eliminated. On cooked chicken, 2 logs (99%). The sprays applied to the same samples? 0,57 and 0,08 logs. Practically nothing. The difference is not marginal: it is the difference between a safe product and one that ends up being recalled from the market.
The team also tested cocktails of bacteriophages multiple: T7 phages against E. coli and FelixO1 against Salmonella, applied together. Reduction: 2,2 logarithms for E. coli (96,5%) and 1,46 for Salmonella (99,4%). It also works against multiple pathogens simultaneously.
From laboratory scale to industrial production
The researchers built a prototype that combines 56 patches of microneedles in a unified structure. A total of 1.792 microscopic needles. The idea is to apply it on food production lines to decontaminate whole products without altering their flavor, odor, or texture. The food's organoleptic properties remain intact.
Zeinab Hosseinidoust, which leads research on bacteriophages to the McMaster, explains that the next step is to test the microneedles against bacteria that cause food spoilage. Not only safety, but also shelf life extension. Regulatory approvals will be needed first, however. For food, they could arrive more quickly than for medical applications.
Technology solves a decades-old problem: how to bring the bacteriophages where they are really needed. The sprays were a compromise. microneedles They're the solution that works. And the numbers prove it.
