I used to trust the California Olive Ranch brand for olive oil, but lately noticed they started labeling their some of their bottles as imported and accidentally bought some. It tastes fine, but if I recall correctly the problems with olive oil usually come from imports where laws and regulation rules change from country to country.

Luckily I live close to a real olive mill, but there really is no way to know. Plus you have people arguing the vast majority of olive oil sold in the USA is "authentic" for some measure of authentic, which is really hard to discern: https://www.aboutoliveoil.org/the-facts-about-uc-davis-olive...

This feels like another one of those areas where as a consumer following the research and knowing what products are good to buy is almost a full time job.