Your glass bottles could have 50 times more microplastics than plastic ones: findings from a new French study

It was published in the Journal of Food Composition and Analysis, as reported by AFP.

Plastic from the caps, not the glass

The research team initially expected glass to be safer. “We expected the opposite result,” PhD student Iseline Chaib, who led the research, told AFP. But upon closer analysis, they found the microplastics were identical in shape, colour and polymer composition to the paint on the caps sealing the glass bottles, not the glass itself.

The paint appeared to be shedding microscopic plastic particles, likely due to friction between caps during storage, ANSES explained in a statement.

Interestingly, flat and sparkling water showed relatively low levels of microplastics across all packaging types: about 4.5 particles per litre in glass bottles compared to 1.6 particles in plastic ones. Wine also had few detectable microplastics, even when sealed with caps similar to those on soft drinks or beer bottles.

The reason for this remains unclear, said Guillaume Duflos, research director at ANSES.

Soft drinks and beer show higher microplastics

Drinks like soft drinks, lemonade, and beer had notably higher microplastic counts, ranging from 30 to 60 particles per litre. These beverages are more commonly sealed with painted caps, which appear to contribute significantly to the contamination.

Currently, there’s no global standard defining what level of microplastics in food or drink may pose a health risk. So, it is not possible to say whether these figures represent a health threat, as per ANSES.

However, the agency did test a possible solution: cleaning the caps with air, water, and alcohol, which reduced contamination by 60%—a fix it said could be adopted by drink manufacturers.

(With inputs from AFP)