A study by France's food safety agency found that glass bottles may contain up to 50 times more microplastics than plastic ones due to particles from bottle caps.
Microscopic scratches in the painted surface of the caps could cause plastic particles to transfer from one cap to another and ultimately fall into the bottle.
Different beverages have varying levels of microplastic contamination, with beer topping the list at around 60 particles per liter.
The research team recommends rinsing bottle caps before sealing or avoiding painting the caps to reduce microplastic contamination in glass bottles.