A newly identified virus that infects bacteria, called phage W5, could help control dangerous salmonella on foods and equipment. The discovery points to a greener, more targeted way to keep the food supply safe.
A virus that hunts bacteria could become a powerful new weapon against salmonella, one of the world’s most common causes of foodborne illness.
Researchers in China have identified a bacteriophage, or phage, that specifically attacks salmonella and can break down the hard-to-kill biofilms the bacteria form on foods and food-processing equipment. Their work, published in the journal Applied and Environmental Microbiology, suggests this phage, called W5, could form the basis of a new generation of targeted disinfectants and preservatives.
The study tackles a growing problem in food safety: salmonella strains that no longer respond well to antibiotics and can survive standard cleaning methods. Salmonella can contaminate foods such as milk, meat and eggs, and it often forms slimy, protective layers known as biofilms on surfaces in farms and processing plants. Those biofilms shield the bacteria from heat, chemicals and other stresses, making them difficult to remove.
At the same time, heavy reliance on antibiotics in agriculture and medicine has helped drive the rise of antimicrobial resistance, limiting treatment options when people get sick. That has pushed scientists to look for alternatives that can control harmful bacteria without adding to the resistance problem.
Bacteriophages offer one such option. These are viruses that infect and kill bacteria but do not infect people, animals or plants. Because each phage usually targets only specific types of bacteria, they can act like a precision tool rather than a broad-spectrum chemical.
In the new study, the research team collected wastewater and isolated multiple phages that could infect salmonella. From that group, they selected the most effective candidate, W5, for detailed testing.
They examined W5’s structure under the microscope, tested how stable it was under different conditions, and measured how quickly it could infect and kill salmonella cells. They also sequenced its genome to check for genes that might make it unsafe, such as genes for toxins or antibiotic resistance.
The team found that W5 was both potent and highly specific, according to corresponding author Huitian Gou, a professor at Gansu Agricultural University’s College of Veterinary Medicine in Lanzhou.
“We discovered a safe and highly effective natural virus (bacteriophage W5) that functions like a precision-guided missile, capable of eliminating harmful Salmonella on various foods and packaging materials, showing great potential as a novel guardian for food safety,” Gou said in a new release.
In lab tests that mimicked real-world storage conditions, the researchers evaluated how well W5 could reduce salmonella on foods including milk, meat and eggs, as well as on food-contact surfaces. They also looked at its ability to disrupt established biofilms, which are often more resistant to cleaning than free-floating, or planktonic, bacteria.
“The research demonstrates that W5 can efficiently lyse planktonic bacteria and eradicate biofilms with high specificity. Genomic analysis further confirms its safety profile, as it lacks virulence and antibiotic resistance genes,” Gou added.
Those findings suggest W5 could be developed into sprays, rinses or coatings that help keep foods and equipment free of salmonella, without leaving chemical residues. Because phages are natural biological entities that break down over time, they are often described as a more environmentally friendly, or green, approach to decontamination.
The team also sees potential for using W5 at multiple stages of the food system, not just in factories or kitchens. Gou noted the phage could be built into a broader strategy that follows food from production to plate.
“We firmly believe that phage W5 holds immense potential for seamless integration across the entire from farm to fork supply chain. It can be incorporated into multiple critical stages—for instance, as a feed additive in livestock farming, a surface disinfectant in meat processing plants, or even a preservative spray for fresh produce at the consumption end,” Gou said.
If that vision becomes reality, phage-based products might one day help farmers reduce salmonella in animals before they reach slaughterhouses, help processors keep equipment and workspaces cleaner, and help retailers and consumers keep fresh foods safer for longer.
For now, W5 remains in the research phase. Before it can be widely used, scientists and regulators will need to confirm its safety and effectiveness in larger-scale trials, understand how it behaves in complex food systems, and develop practical ways to manufacture and apply it consistently.
The researchers are already thinking ahead to that next step.
“We eagerly look forward to collaborating with industry partners to translate this effective green solution from the laboratory to the market, working together to safeguard food safety,” added Gou.
If successful, W5 and similar phages could become part of a toolkit that includes better hygiene, smarter processing and more careful antibiotic use. Together, those measures could help curb foodborne disease and slow the spread of antibiotic resistance, while meeting consumer demand for cleaner labels and more sustainable production.