Glass bottles may not be as safe as commonly believed. A new study by France’s food safety agency (ANSES) has found that drinks such as water, soda, beer and wine sold in glass containers contain more microplastics than those sold in plastic bottles. This finding challenges the widespread perception of glass as a cleaner or healthier packaging option, reported Phys.org.
Guillaume Duflos, research director at ANSES, said his team sought to ‘investigate the quantity of microplastics in different types of drinks sold in France and examine the impact different containers can have’. The study compared various beverages packaged in materials such as glass and plastic, aiming to understand how packaging influences microplastic content.
The researchers discovered that glass bottles of soft drinks, lemonade, iced tea and beer contained an average of around 100 microplastic particles per litre – 5 to 50 times more than the amounts found in plastic bottles or metal cans. One likely source of contamination is the paint on the caps, which showed microscopic scratches likely caused by friction during storage. These scratches could then release particles onto the surface of the caps.
Still and sparkling water showed relatively low levels of microplastics across all types of packaging, with glass bottles containing around 4.5 particles per litre, and plastic bottles showing the lowest concentration, at just 1.6 particles per litre.
Bottles of wine contained only minimal levels of microplastics, even when bottled in glass with caps – a discrepancy that, according to Duflos, ‘remains to be explained’. In contrast, other beverages had significantly higher concentrations, with soft drinks containing around 30 particles per litre, lemonade around 40, and beer reaching approximately 60.
ANSES noted that, in the absence of a defined reference level for potentially harmful microplastic exposure, it is not yet possible to determine whether these amounts pose a health risk. However, it stressed that drink manufacturers could reduce contamination by limiting the shedding of particles from bottle caps.
The agency tested a cleaning method involving blowing air over the caps followed by rinsing them with water and alcohol. This approach proved effective, reducing microplastic contamination by up to 60%.
