"We expected the opposite result," Ph.D. student Iseline Chaib, who conducted the research, told AFP.
"We then noticed that in the glass, the particles emerging from the samples were the same shape, color and polymer composition—so therefore the same plastic—as the paint on the outside of the caps that seal the glass bottles," she said.
The paint on the caps also had "tiny scratches, invisible to the naked eye, probably due to friction between the caps when there were stored," the agency said in a statement.
This could then "release particles onto the surface of the caps," it added.
OK, so maybe a minor change in how these bottles are filled and sealed could end up fixing the issue. There's clearly some issues with soft drink assembly lines, and if these can be addressed, then the overall amount of microplastics can be mitigated. Seems like we need to start phasing plastics out of every step of manufacturing if we want to end microplastics in food and drink.
All of these factory spaces have metrology departments for confirming product specifications are in spec, who are likely to have training and expertise in defect isolation (as in finding where a defect is coming from). I have very little doubt that they would be able to create/purchase the necessary tools for checking for microplastic dispersion within the factory floor and isolating the key locations that need fixing. That is, if regulations started requiring and testing for lower microplastic content.