U of I Study Finds Nanoplastics Alter Salmonella Virulence

Researchers say microscopic plastic particles can increase pathogen's virulence and stress response.

Published on Feb. 27, 2026

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Researchers at the University of Illinois Urbana-Champaign have found that brief exposure to nanoplastics, microscopic plastic particles that form as plastics break down, can increase the virulence of Salmonella enterica, a leading cause of foodborne illness. The study, published in the Journal of Hazardous Materials, showed that nanoplastics led to increased expression of virulence-related genes and thicker biofilm formation in Salmonella. However, prolonged exposure appeared to weaken the bacteria's stress response.

Why it matters

Salmonella is a major foodborne pathogen often found in meat, poultry, and ready-to-eat foods. The researchers' findings raise new food safety concerns, as plastic packaging is commonly used for these products. The study also suggests nanoplastics may contribute to antibiotic resistance in bacteria.

The details

The researchers examined how polystyrene nanoplastics affect Salmonella enterica. They found that brief exposure to nanoplastics increased the expression of virulence-related genes and led to thicker biofilm formation, indicating the bacteria were becoming more virulent. However, prolonged exposure appeared to weaken the bacteria's stress response, as they went into a defensive mode to conserve resources and energy.

  • The study was published on February 27, 2026.

The players

Pratik Banerjee

Associate professor of food science and human nutrition at the University of Illinois Urbana-Champaign and senior author of the study.

Jayita De

Graduate student and lead author of the study.

Salmonella enterica

A leading cause of foodborne illness that is often found in meat, poultry, and ready-to-eat foods.

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What they’re saying

“Salmonella enterica is a major foodborne pathogen that is often found in meat, poultry, and ready-to-eat food. We are testing ground turkey from grocery stores in our lab for a study on food safety, and finding that it is frequently positive for Salmonella. If you cook the meat properly, you should not have a problem. However, ground turkey is often packaged in plastic, and we wanted to explore how Salmonella react when they come into contact with plastic polymers.”

— Pratik Banerjee, Associate professor of food science and human nutrition (Chambana Today)

“We examined the physiology of Salmonella in response to nanoplastics, and we found an increased expression of virulence-related genes. The bacteria also formed thicker biofilms, which further indicates they are becoming more virulent.”

— Jayita De, Graduate student (Chambana Today)

“When the bacteria first encounter nanoplastic particles, they go into offensive mode and become more virulent. But after a while, they start losing their resources and energy, so they switch to defensive mode, which allows them to persist in the environment for a longer time. If the concentration of nanoplastics rises, they can again switch to an offensive mode. It's a trade-off between offense and defense.”

— Jayita De, Graduate student (Chambana Today)

What’s next

The researchers say more study is needed to determine the broader public health implications and whether the findings warrant policy changes.

The takeaway

This study highlights the potential for nanoplastics, which are formed as plastics break down, to influence the behavior of foodborne pathogens like Salmonella. While more research is needed, the findings raise new food safety concerns and suggest nanoplastics may contribute to antibiotic resistance in bacteria.