Plastic is commonly found in canned food and drink. The foods are boiled inside plastic lined containers to ensure safety. Feed is sometimes ground up human waste aka moldy bread with plastic that's been ground up that the animals eat.

Here are more ways you can ingest them. https://www.earthday.org/you-are-what-you-eat-plastics-in-ou... Apples and carrots were not expected to be the most contaminated.