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Glass and Microplastics

What Recent Research Found — and What It Missed

Recent studies raised questions about microplastics and glass packaging. Here's what the research actually found, what independent scientists say, and why glass remains an inert, trusted choice.
Glass & Microplastics: What Consumers are Asking
  • Do glass bottles contain microplastics?
  • Is glass better than plastic for food and beverages?
  • What do recent studies actually say—and what did headlines miss?

Over the past few years, microplastics have become part of the public conversation about health, food safety, and the materials we use every day. Understandably, consumers want clear, science-based answers, especially when headlines seem to suggest puzzling conclusions.

This page takes a closer look at what the science actually shows about glass and microplastics, how it’s been interpreted, and what really matters when it comes to packaging choices.

French Researchers Clarify Findings on Glass & Microplastics

In May 2025, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) published a study measuring microplastic particles in a range of beverages packaged in different formats, including plastic, metal, carton, and glass.

Early headlines made it sound like glass bottles were the problem. But when independent researchers, and ANSES itself, looked more closely, a different picture emerged.

The key findings:

  • The microplastics detected were not traced to the glass packaging itself.
  • Investigators traced the particles primarily to painted metal caps and closures, not the glass containers themselves.
  • Beverages bottled in glass with natural cork closures, such as certain wines, did not show elevated microplastic levels.

ANSES later clarified that closures – not glass – were the dominant source of microplastic contamination in glass-packaged beverages.

What Scientists Confirm about Microplastics in Packaging

As media coverage of the ANSES findings spread, an international group of scientists led by Dr. Jane Muncke of the Food Packaging Forum published a formal scientific comment addressing the findings’ interpretation.

Their response, published as a comment in the Journal of Food Composition and Analysis, highlighted several important points:

  • Glass itself cannot generate microplastics because it is not a plastic and does not fragment into polymer particles.
  • Comparing containers without accounting for closures, linings, and processing equipment can lead to misleading conclusions.
  • Microplastics can enter food and beverages from many points in the manufacturing process beyond the container, including caps, bottling lines, and handling.

In short, they emphasized the need to look at the whole system for sources of microplastic contamination – not just the container.

The Glass Packaging Institute (GPI) reached a similar conclusion, noting that:

  • Glass does not release microplastics.
  • Where microplastics were detected in glass-packaged beverages, they were linked to painted metal caps or closure management, not the glass container.
  • Improved closure hygiene and handling may help limit detected particles.

GPI welcomed ANSES’s clarification and called for more precise communication to avoid confusing consumers.

What "FDA GRAS" Status Means for Glass
In the United States, glass has long been recognized by the Food and Drug Administration (FDA) as safe for use in contact with food. The FDA considers glass as “generally recognized as safe” (GRAS) for food-contact use, based on its extensive history and well-understood profile.

Glass is virtually inert

It does not react with food or beverages.

Glass does not leach

Glass does not leach chemicals into food.
For consumers, this longstanding recognition reflects something straightforward but important: glass behaves predictably and transparently in contact with food, helping protect taste, quality, and food integrity.
What Health Organizations say about Limiting Plastic Exposure

As concerns about chemical exposure have grown, several medical organizations have encouraged limiting contact with certain plastics when you can, including in food packaging, as a precautionary measure.

American Academy of Pediatrics (2018): Encouraged families to limit plastic food containers and packaging when possible, particularly for children.

American College of Obstetricians and Gynecologists (2021): Recommended reducing exposure to potentially harmful environmental chemicals during pregnancy, including those associated with certain plastics.

Both organizations emphasize reducing unnecessary exposure to certain plastic-associated chemicals, particularly where practical alternatives exist.
How O-I Thinks About Glass Packaging Design

At O-I, we focus on bringing clarity to complex questions about materials and packaging. As glass packaging manufacturers, this is how we think about design in the context of glass, microplastics, and food-contact packaging.

In many packaging formats, additional layers or liners are used as part of container design. Glass, by contrast, generally does not require an interior plastic or chemical liner, making it a simpler material system compared to formats that rely on additional layers.

1

Glass is virtually inert

Research on microplastics, including recent studies on glass packaging, shows that caps, linings, and handling all play a role. That’s why responsible packaging design has to look beyond the container and consider the full system, including closure materials and hygiene.

2

Glass fulfills the core role of packaging

Glass protects food and beverages without introducing additional material interactions. Glass is:
  • Inorganic and non-plastic
  • Odor- and flavor-neutral
  • Virtually inert
  • Made from four simple ingredients: sand, limestone, soda ash, and recycled glass
3

Prioritize predictability in packaging design

Packaging systems can vary widely depending on materials, coatings, closures, and handling. In our view, simpler, well-understood materials like glass introduce less variability in how packaging behaves over time.

Taken together, these design principles reflect a consistent theme in microplastics research: understanding packaging requires looking beyond any single component to how the full system is designed and managed.
What This Research Means for Glass Packaging

Simple, well-understood materials reduce uncertainty. Glass has been trusted for generations to protect food and beverages.

Microplastics research is evolving, and so should how we talk about it. When you step back and consider the full body of evidence, the conclusion is consistent: glass itself is not a source of microplastics.

By looking beyond headlines and focusing on material science, system design, and independent expertise, consumers can better understand what the science does, and does not, show.

Research & References

Microplastic contaminations in a set of beverages sold in France
Chaib et al. · Journal of Food Composition and Analysis · May 19, 2025

Comment on “Microplastic contaminations in a set of beverages sold in France”
Muncke et al. · Journal of Food Composition and Analysis · September 19, 2025

GPI Statement in Response to Misleading Microplastics Study
Glass Packaging Institute · June 24, 2025

Food Additives and Child Health (Policy Statement)
American Academy of Pediatrics · August 1, 2018

Reducing Prenatal Exposure to Toxic Environmental Agents (Committee Opinion)
American College of Obstetricians and Gynecologists · July 2021

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