So, some important context. Unlike the EU and other modern nations, the US sets rates above which regulatory action must be taken. Regulatory action may still be taken below those limits depending on the circumstances. Most places have no line above which action must be taken. This is the US being more strict than normal, not less strict.

Contaminants are a part of life. "No contaminants" is not a real option. Inspectors in the US and elsewhere look at the process and determine if appropriate controls are in place. If they're not they may take action, regardless of the amount of contaminants. This is how most nations work. The US is different because we require action when above a said amount.

Big thing to remember is that it isn't "you can have up to this much without regulatory action." It's "you must control for contamination and we'll consider context for deciding what's acceptable unless it rises above the max and then we have to take action."