Don’t buy olive oil from big brands (Bertoli), best buy Spanish olive oil, as Spain has most strict controlled production processes.
Discussion
The only right way is to buy olive oil, directly from your nearest local producer who makes it with passion.
Every industrialized oil is simply crap.
Agree.
In Europe, there are small boutique importers of quality olive oils, made by passionate producers in Italy, Greece, Spain.
Just an example (in Dutch) :