Scientific research is of critical importance to food safety, improving industry professionals’ and regulators’ understandings of and ability to address both longstanding and emerging threats. Like in years prior, the 2025 Top Ten round-up summarizes the learnings and discoveries uncovered by food safety researchers—and covered by Food Safety Magazine—throughout the year, chosen based on which stories attracted the most attention from our readers.

In 2025, our coverage of research about Listeria monocytogenes, especially related to biofilms, dominated the Top Ten list. Also included are research projects about microplastics, Escherichia coli, antimicrobial resistance (AMR), avian influenza in dairy, microbial threats in irrigation water, and food allergens.

Highlighted below are the ten food safety research projects that captured the attention of our audience in 2025, listed in descending order, with links to detailed coverage about each study at the end of each section.

The Top Ten Most Popular Food Safety Scientific Studies of 2025

10. Study Shows Food Type Significantly Affects Listeria’s Ability to Survive Digestion, Cause Sickness

A study in npj Science of Food highlights how the type of food matrix can shape the survival and virulence of L. monocytogenes during digestion. Researchers from the University of Vienna tested three common ready-to-eat (RTE) foods—knackwurst sausage, smoked salmon, and brie cheese—by inoculating them with multiple Listeria strains and storing them at 10 °C for seven days. While overall growth was similar across food types, strain-specific differences emerged, and transcriptomic analysis revealed metabolic adaptations tied to each matrix. For example, cheese prompted upregulation of sugar metabolism genes, sausage influenced amino acid synthesis pathways, and fish activated protein translation and ribosomal functions. These findings underscore the role of food composition in pathogen behavior, with smoked fish and soft cheese posing heightened risks for L. monocytogenes survival and infection.

Read more about the study here.

9. Study Shows Combining Antimicrobial Blue Light and Chemical Sanitizers Can Enhance Listeria Inactivation

A study published in the Journal of Food Protection by researchers at the University of Georgia explored the combined use of antimicrobial blue light (aBL) and low concentrations of common sanitizers to inactivate L. monocytogenes on food contact surfaces. The team tested sodium hypochlorite, peracetic acid, and benzalkonium chloride alongside aBL at 405 nanometers (nm) on stainless steel and polytetrafluoroethylene (PTFE, commonly known as Teflon) coupons inoculated with five Listeria strains. While individual treatments achieved modest reductions, simultaneous application of aBL with any sanitizer produced significantly greater reductions than the sum of separate treatments, indicating a synergistic effect. Sequential treatments also improved inactivation, though results varied by sanitizer type, concentration, surface material, and treatment order. These findings suggest that pairing aBL with low levels of sanitizers could enhance pathogen control strategies in food production environments.

Read more about the study here.

8. Microplastics Increase Antibiotic Resistance of E. coli, Aid Biofilm Formation, Study Shows

A study published in Applied and Environmental Microbiology by Boston University researchers reveals that microplastics may accelerate AMR and multi-drug resistance in E. coli. The team found that biofilms formed on microplastics were significantly stronger and thicker than those on glass, correlating with higher rates of AMR development. When E. coli was exposed to microplastics alongside antibiotics, 81 percent of bacteria retained or increased resistance even after antibiotic exposure ceased, compared to 19 percent in antibiotic-only conditions. Resistance was observed across all tested antibiotics—ampicillin, ciprofloxacin, doxycycline, and streptomycin—with polystyrene microplastics showing the greatest effect. These findings underscore the potential role of microplastics as unique substrates that foster resilient, drug-resistant pathogens, posing a growing food safety and public health concern.

Read more about the study here.

7. Listeria From Multispecies Biofilms More Prone to Growth in RTE Foods, Study Shows

A study published in npj Science of Food examined how L. monocytogenes biofilms contribute to cross-contamination in RTE environments, focusing on cold-smoked salmon. Researchers from the Spanish Higher Council for Scientific Research (CSIC) and the University of Córdoba modeled Listeria transfer from single- and multispecies biofilms to salmon slices across 25 successive contacts, finding that multispecies biofilms promoted significantly higher pathogen growth post-transfer. Biofilm structure influenced detachment dynamics, with three stages—initial, unstructured, and inner-layer transfer—presenting unique contamination patterns. Next, in a case study simulating new EU regulatory limits, salmon contaminated by multispecies biofilms exceeded the 100 CFU/g threshold after 15 days of refrigerated storage, while single-species contamination remained lower. These findings highlight the need to consider multispecies biofilms in challenge studies and reinforce stricter controls under updated European Commission microbiological criteria for Listeria in RTE foods.

Read more about the study here.

6. Study Demonstrates Listeria’s Ability to Colonize, Survive in Preexisting Multispecies Biofilms

A study published in Microbiological Research shows that Listeria monocytogenes can colonize preexisting multispecies biofilms within hours and persist over time, potentially gaining protection against cleaning and disinfection in food processing environments. Researchers from Austrian food safety and veterinary academic establishments introduced a strain of L. monocytogenes (ST121) to biofilms composed of common environmental bacteria on stainless steel and observed colonization within two hours, with the pathogen accounting for 6.4 percent of cells after six hours and surviving for seven days without altering the biofilm’s structure. The study also confirmed Listeria’s ability to attach to stainless steel and form monospecies biofilms, though these lacked complex three-dimensional structures, consistent with its weak biofilm-forming capacity by itself. Both biofilm types supported Listeria multiplication, suggesting that multispecies communities provide a favorable environment for persistence. Overall, the findings indicate that L. monocytogenes may act as a passive resident in biofilms rather than an active disruptor, complicating control efforts in food production settings.

Read more about the study here.

5. First-of-its-Kind Study Shows How Listeria Strains Evolve Into Strong Biofilm Formers

A study published in Microbiological Research by Wageningen University scientists explored the genetic and phenotypic adaptations that enable L. monocytogenes to evolve into strong biofilm formers. Using experimental evolution, researchers isolated evolved variants from two strain backgrounds that showed up to seven-fold higher biofilm production compared to their ancestors. Increased cell surface hydrophobicity emerged as a key trait, linked to mutations affecting the lmo1798–1799 operon, with overexpression of lmo1799 driving enhanced attachment to hydrophobic surfaces like stainless steel and polystyrene. Proteomic and genomic analyses confirmed that these mutations alter surface charge and biofilm architecture, while also potentially influencing stress resistance and virulence. This study marks the first use of experimental evolution to uncover biofilm-enhancing mutations in L. monocytogenes, offering critical insight into evolutionary mechanisms that lead to traits that complicate pathogen control in food processing environments.

Read more about the study here.

4. FDA-Backed Study Shows Aging Raw Milk Cheese Does Not Inactivate Avian Flu, but Low pH Helps

A Cornell University study published in Nature Medicine, funded by the U.S. Food and Drug Administration (FDA) and New York State, found that aging raw milk cheese for 60 days does not reliably inactivate Highly Pathogenic Avian Influenza H5N1 (HPAI H5N1) virus. Researchers tested virus stability during cheesemaking and aging under different pH conditions and discovered that the virus persisted for 60 days in cheeses with pH 6.6 and 5.8, but was inactivated at pH 5.0. Heat treatments during production also reduced viral loads, suggesting that either adequate heat or low pH can effectively control HPAI H5N1. These findings challenge the assumption that the 60-day aging rule alone ensures safety, highlighting potential public health risks from raw milk cheeses. The study underscores the need for additional mitigation steps in cheesemaking and aligns with FDA’s broader research agenda on dairy safety amid the ongoing HPAI H5N1 outbreak among U.S. dairy cattle.

Read more about the study here.

3. Experts Recommend Four Hidden Food Allergens for Mandatory Labeling in EU

A study published in Clinical and Experimental Allergy analyzed 2,999 food-induced anaphylaxis (FIA) cases reported to the Allergy-Vigilance Network (AVN) from 2002–2023 to identify emerging food allergens not currently regulated under EU labeling laws. AVN-associated researchers found that eight foods—goat/sheep milk, buckwheat, peas/lentils, pine nuts, red meat via alpha-gal, kiwi, beehive products, and apples—accounted for 13.8 percent of FIA cases, with some causing more reactions than allergens already on the EU mandatory labeling list. Goat/sheep milk and buckwheat ranked above several regulated allergens, while peas/lentils and pine nuts also showed significant prevalence. Based on severity, recurrence, and hidden presence in foods, the study recommends adding goat/sheep milk, buckwheat, peas/lentils, and pine nuts to the EU list of major allergens. The findings underscore the need to update allergen labeling legislation, which has remained unchanged since 2011, to better protect consumers with food allergies.

Read more about the study here.

2. Half of Romaine Lettuce E. Coli Outbreaks Caused by Overhead Irrigation Water, Study Finds

A U.S. Department of Agriculture (USDA)-funded study published in Scientific Reports by Cornell, Virginia Tech, and University of Florida researchers used a quantitative microbial risk assessment (QMRA) model to identify key drivers of E. coli O157:H7 contamination in romaine lettuce. The model revealed that 52 percent of illnesses linked to romaine occur due to untreated overhead irrigation water, making it the most significant preharvest risk factor. Switching to drip or furrow irrigation or treating water could reduce contamination risk by up to 96 percent, but postharvest interventions like consumer washing and retail temperature control were far less impactful. Maintaining the cold chain after harvest was found to be critical for minimizing illness severity during outbreaks. The findings provide actionable strategies for growers and regulators to prioritize irrigation practices in reducing E. coli risks in leafy greens.

Read more about the study here.

1. Study Shows Water Hoses as Reservoirs for Biofilms in Food Processing Facilities

A study by Austrian food safety and veterinary researchers published in the Journal of Food Protection found widespread microbial colonization in water hoses used in a meat processing facility, confirming their role as potential reservoirs for biofilms. Over eight months, biofilms were detected in 14 of 15 hoses, which were fed a drinking water-quality supply and made of uniform hose material. Notably, the hoses did not have a regular cleaning schedule. Microbial communities included opportunistic pathogens such as Mycobacterium, Legionella, and Pseudomonas. Fungal species were also present, notably Trichoderma, which has been linked to human infections, raising additional food safety concerns. Biofilm presence did not correlate with hose usage frequency or sampling time, suggesting that other operational factors influence development and highlighting gaps in routine cleaning practices. The findings underscore the need for regular monitoring and maintenance of water delivery systems to mitigate contamination risks in food processing environments.

Read more about the study here.

Honorable Mentions: Microplastics

Among the top-ranking scientific stories of 2025 are three studies investigating the release of microplastics into foods from food contact materials (FCMs) and the presence of microplastics in seafood. This area of interest is one to keep an eye on; although these three popular articles may not have immediately actionable implications for industry, dietary exposure to microplastics is gaining attention not only from the Food Safety Magazine audience, but also from academia and even food safety regulatory authorities.

In fact, before jumping into the three microplastics studies that have received honorable mentions in this year’s scientific round-up, it is worth mentioning a literature review published by the European Food Safety Authority (EFSA) in October which concludes that, while there is clear evidence of microplastic release from FCMs, the actual quantities are likely lower than many studies suggest. Nanoplastics data remain insufficient, and current evidence does not support reliable exposure estimates. Read more about EFSA’s literature review here.

With that context in mind, the top three articles on microplastics, which were among the most-read scientific articles published by Food Safety Magazine in 2025, are:

1. Study Shows Chewing Gum Releases Thousands of Microplastics, Whether Gum is Synthetic or Natural: Researchers at the University of California, Los Angeles (UCLA) found that chewing gum—whether synthetic or plant-based—can release hundreds to thousands of microplastic particles into saliva, with most particles released within the first two minutes of chewing. On average, 100 microplastic particles are released per gram of gum, meaning a single piece could release up to 3,000 particles, contributing significantly to annual microplastic ingestion. While the health effects remain unclear, the study suggests reducing exposure by chewing fewer pieces for longer periods and highlights the pervasive nature of microplastics in everyday foods. Read more about the study here.
2. Study Shows Tea Bags Release Millions of Microplastics When Brewed: Researchers at the Autonomous University of Barcelona found that commercial tea bags made from nylon-6, polypropylene, and cellulose release millions to billions of nano- and microplastic particles when brewed. These particles, some as small as 136 nanometers, were shown to be absorbed by human intestinal cells, even entering cell nuclei, suggesting potential health risks. The study calls for further research on chronic exposure and the development of standardized testing and regulatory policies to address plastic pollutants from food contact materials. Read more about the study here.
3. Oregon-Based Study Shows Widespread Microplastics Contamination in Seafood: Portland State University and Oregon State University researchers found widespread microplastics contamination in Oregon seafood, with 180 out of 182 samples containing particles, primarily fibers that can migrate into edible muscle tissue. Pink shrimp had the highest concentration of microplastics while Chinook salmon had the least, and rinsing retail fish sometimes reduced surface contamination. Despite these findings, scientists emphasize that microplastics are pervasive across many food types and are working on solutions like filtration systems to reduce environmental contamination. Read more about the study here.