The Dangers of Paper Straws: An Interview with Elena Canellas and Paula Vera

For years now, plastic straws have been decreasing in popularity due to their environmental risks. Plastic was found in approximately 90% of all seabirds and in all sea turtles species in a 2018 World Wildlife Fund study, with scientists claiming, “Within the next decade, there could be a pound of plastic for every three pounds of fish in the ocean” (1).

As such, the most popular alternative has been to use paper straws instead. While these are biodegradable, they have also been found to be problematic. In a 2024 study led by Elena Canellas and Paula Vera of the University of Zaragoza in Spain, it was discovered thatseveral concerning compounds that migrate from paper straws, such as bis(2-ethylbutyl)phthalate and dioctyl phthalate, both recognized as endocrine disruptors, and 4,4'-methylenedianiline, a primary aromatic amine and suspected carcinogen, into soda. This shows that despite the difference in materials, paper straws may not be the safest alternative to plastic straws when it comes to food safety (2).

White paper straws in glass, Sustainable lifestyle concept | Image Credit: © shersor - stock.adobe.com

Recently, LCGC International interviewed Canellas and Vera about their research, learning the dangers of paper straw use, alternative solutions, and the future of their studies.

Was soda contamination previously a concern with plastic straws? If so, how much?

Concerns regarding plastic migration from straws into soda focus on the transfer of chemical substances, particularly under specific conditions. Key issues involve chemical leaching, where substances intentionally added to the plastic—such as bisphenol A (BPA), phthalates, and other additives—can migrate into beverages. These compounds are of particular concern as potential endocrine disruptors, potentially impacting hormone regulation. Additionally, other intentionally added substances (IAS)—such as antioxidants, plasticizers, slip agents, inks, antibacterial agents, and other compounds commonly added to enhance the properties of plastics—can also migrate into drinks. Beyond IAS, non-intentionally added substances (NIAS), including oligomers, impurities, and degradation by-products, may also transfer. NIAS can result from the breakdown of IAS or reactions between IAS and components in acidic beverages like soda or citrus drinks. The risk of leaching intensifies with exposure to acidity, heat, or extended contact. This is particularly relevant for soda, which commonly has high acidity levels that enhance migration, and for hot beverages like milk, which some children consume with straws, as heat accelerates chemical leaching. Additionally, microplastic release is another concern; as plastic straws degrade, they may shed tiny particles into beverages, though this risk remains low in single-use applications.

Why are inks present in paper straws? With the potential for material transfer and contamination, why are these substances still being used?

Inks are commonly used on paper straws for branding and aesthetic purposes, helping to enhance the visual appeal of beverages and promote products effectively. In Europe, the regulation of inks for packaging is primarily covered by Regulation (EC) No 1935/2004, which establishes that materials and objects intended to come into contact with food, including inks, must be safe and not transfer substances to food in amounts that could be harmful to health. Nevertheless, in contrast to plastics used in food contact applications, there is no specific approved list of compounds for ink formulations. However, it's important to be aware that these inks can contain a variety of IAS and NIAS that may transfer to drinks. This includes substances like primary aromatic amines, which are known to be carcinogenic, as well as other compounds with varying levels of toxicity. While manufacturers often strive to use food-safe inks, the potential for harmful chemicals to leach into beverages raises concerns about safety and health risks. This highlights the need for ongoing research to ensure that materials used in food contact products are safe for consumers, balancing the desire for attractive packaging with the imperative of public health.

If paper straws are not a safe alternative to plastic straws, do you have any ideas as to what could be a safe alternative?

Reusable alternatives like stainless steel and glass straws are safe for food use and strongly support a circular economy by significantly reducing waste and minimizing reliance on single-use products. Stainless steel straws are durable, corrosion-resistant, and do not react with hot or cold beverages, making them ideal for long-term use across a wide variety of drinks. They are easy to clean and maintain, especially when paired with cleaning brushes, and they remain free from harmful chemicals, supporting safer consumption over time. Glass straws, similarly, are non-toxic, recyclable, and visually transparent, allowing users to verify cleanliness easily. These materials are crafted to withstand repeated use, which keeps them in circulation and out of landfills, thus reducing overall resource consumption.

Are you and your team planning to expand your findings in this study further with more research?

Yes, we are planning to expand on our findings in future research. We believe that building on this study with additional data and a larger sample size will help us deepen our understanding of the topic. Specifically, we are considering exploring the most volatile migrants that weren’t analyzed in the present study. This continued research could provide valuable insights and strengthen the foundation for practical applications based on our findings.

How is it possible that the same additives/compounds can be found in both paper and plastic?

Certain chemical additives are employed in both paper and plastic products due to their effectiveness in enhancing material performance and longevity. Waterproofing agents, for example, are used for their hydrophobic and oleophobic properties, making both paper and plastic resistant to moisture and oil, essential for preventing structural degradation in food packaging and disposable utensils. Binders are included in paper to strengthen cellulose fibers, while similar compounds act as structural reinforcements in plastics, improving cohesion and durability. Colorants and pigments are employed for visual consistency and opacity, as these compounds offer high thermal stability and chemical resistance suitable for multiple applications. Further, ultraviolet (UV) stabilizers, are applied to prevent photo-oxidative degradation in both materials, which is critical in prolonging product life under UV exposure. Antimicrobial agents are also incorporated to inhibit microbial growth and extend shelf life, particularly in products exposed to moist environments. These additives fulfill similar protective and aesthetic functions across both paper and plastic, ensuring functional longevity, improved barrier properties, and resistance to environmental stressors, despite the inherent differences in the molecular composition of paper (cellulose) and plastics (synthetic polymers).

Are there any regulatory bodies overseeing the use of straws in the food chain?

There is no specific regulation dedicated to paper straws; however, all materials and objects intended for contact with food must comply with Regulation (EC) No 1935/2004, which sets out the general requirements for food contact materials. This regulation establishes that such materials must be safe and must not transfer substances to food in amounts that could be harmful to human health. Additionally, the European Food Safety Authority (EFSA) plays a crucial role in assessing the safety of substances used in food contact materials. EFSA publishes scientific recommendations and conducts safety evaluations on chemicals, additives, and substances used in food packaging and utensils, which could also include materials used in paper straws. If a substance, such as an ink or coating used in the manufacturing of paper straws, is deemed potentially harmful, EFSA's guidance may inform regulations and recommendations to ensure consumer safety.

References

(1) A Small Straw’s Big Environmental Impact. WWF 2018. https://www.worldwildlife.org/magazine/issues/summer-2018/articles/a-small-straw-s-big-environmental-impact (accessed 2024-11-15)

(2) Canellas, E.; Vera, P. Exploring Soda Contamination Coming from Paper Straws Through Ultra-High-Pressure Liquid Chromatography Coupled with an Ion Mobility-Quadrupole Time-of-Flight Analyzer and Advanced Statistical Analysis. Food Packag. Shelf Life 2024, 41, 101237. DOI: 10.1016/j.fpsl.2024.101237

About the Interviewees

Elena Canellas is a Ramón y Cajal researcher in the Department of Analytical Chemistry at the University of Zaragoza. She is a biochemistry graduate with a PhD in Analytical Science. With over 15 years of extensive experience in food safety research and the advancement of polymer-based packaging solutions, her expertise encompasses diverse realms, ranging from high-resolution mass spectrometry to the elucidation of unidentified contaminant compounds, along with the innovation of active packaging strategies designed to mitigate food wastage. She has an H-index of 27, with 52 scientific papers published (90% in Q1 journals) and 1,652 citations. She has also participated in numerous national and international projects, over 30 international symposia, and has been actively involved in many dissemination activities.

Paula Vera is a chemical engineer with a PhD in Analytical Science. She is working at the University of Zaragoza on interdisciplinary research in the field of food packaging, focusing on extending shelf life, recycling materials, and ensuring food safety through risk assessment, with particular attention to NIAS (Non-Intentionally Added Substances. She has an H-index of 25 and approximately 1,400 citations. Vera is also the author of 44 SCI articles (91% in Q1 journals) and 6 book chapters. She has actively participated in 40 international and national conferences and been involved in approximately 10 competitive national projects and over 20 contracts with companies.