I had a nutrition class in grad school where they taught us the natural carcinogens in some foods, showing that there was so such thing as a perfectly safe food for everyone.
We can tolerate some toxicity on some foods, so they set limits on known problems. Peanuts have a naturally occurring carcinogen and must be tested in America before they are used for peanut butter. Imported peanut butter may not have been strictly tested. I grew some peanuts one year in an unusually hot, long summer, roasted them and they tasted pretty good. Of course I couldn't test them. But they were natural! I shared them with my squirrels. Dorisena