It’s a problem with bureaucrats that they think the technological ability to detect something at smaller and smaller levels is matched by the ability to remove the pollutant to smaller and smaller levels. However, in the case of something that shouldn’t be there at all, it may be more than just a matter of how many insect parts are allowable in your peanut butter.
Your food is full of contaminants at levels that are considered acceptable. Try dioxins. Notice the article never mentions any level. Trust me, this is a lawyer thing.