Study reveals glass bottle caps as a source of microplastics in beverages

A recent study conducted by the ANSES Food Safety Laboratory has unveiled a surprising source of microplastic contamination in beverages: glass bottle caps. The findings indicate that drinks stored in glass bottles contain significantly higher levels of microplastics compared to those in plastic bottles, cartons, or cans.  

The research aimed to assess the extent of microplastic presence in various beverages, including water, soda, iced tea, wine, and beer. Contrary to expectations, the study found that the average concentration of microplastics in beverages from glass bottles was about 100 particles per liter, which is 5 to 50 times greater than that found in other types of packaging.  

While water and wine showed relatively low levels of microplastics—averaging 4.5 particles per liter in glass bottles and 1.6 in plastic—other beverages were more affected. The study suggests that the primary source of contamination in glass bottles is the paint used on metal caps. The microplastics detected were often found to match the color and composition of this paint.  

ANSES researchers explored how microplastics migrate into beverages. They hypothesized that friction between caps during storage leads to microscopic scratches, releasing plastic particles into the drinks when the bottles are sealed. In experiments, they tested various cleaning methods for caps before bottling. Results showed that uncleaned caps led to an alarming average of 287 microplastic particles per liter. This number significantly decreased with cleaning methods: to 106 particles per liter with air blowing and further reduced to 87 particles after rinsing the caps.  

These findings highlight the potential for manufacturers to mitigate microplastic contamination through straightforward interventions, such as enhancing cleaning protocols and reconsidering the materials used in cap coatings.  

The presence of microplastics in our beverages raises critical questions about health risks, particularly as these particles are known to be pervasive in the environment, affecting food, water, air, and even human health. While the study did not determine the health implications of the observed levels of microplastics, it emphasizes the urgent need for further research to assess consumer exposure and potential health effects.    

Source:  

ANSES