There have been several articles about this previously, and even a book (I'm probably more aware of this than many HN readers since I follow several food blogs.

There have been several articles about this previously, and even a book (I'm probably more aware of this than many HN readers since I follow several food blogs.) Here are some lists of what to buy and not buy: http://lifehacker.com/the-most-and-least-fake-extra-virgin-olive-oil-brands-1460894373 http://lifehacker.com/the-most-and-least-fake-extra-virgin-o... http://articles.courant.com/2012-09-10/business/hc-ls-consumer-reports-olive-oil-20120908_1_california-olive-ranch-olive-oil-extra-virgin http://articles.courant.com/2012-09-10/business/hc-ls-consum... Trader Joe's and Costco were two that consistently came out on top. (For what it's worth, I've been buying the Costco organic EVOO and it's been great. I'm a supertaster and can--fortunately or unfortunately--taste the difference.)