We've shown you how to tell if that pricey bottle of olive oil is worth your money, but here's another one: Check for a seal of approval from the local or regional authority where it was bottled.
As an example, Zester Daily explains that many California olive oils are sent to the California Olive Oil Council's panel of expert testers for certification. The process usually costs a fee, one that doesn't necessarily represent whether the oil will pass. If the oil does pass, the oil company gets to put a much-coveted seal of approval on the bottle to prove their extra virgin olive oil is the real thing and not a mish-mash of oils from various places and pressings.
There are similar councils and authorities around the globe, and all it takes is a quick Google search from your phone in the supermarket to see if the seal is legit. The Australian Olive Association has voluntary guidelines and puts quality seals on approved products.
Zester Daily says that if you're really looking for a universal way to tell a good oil, look for a harvest date before you buy. If the bottle you're holding doesn't have one, that should tell you something on its own.
Similarly, a check of where the bottle is from and where the olives were grown will help you too — the fewer sources of olives for your bottle, the less time the olives spend in transit, being handled, packaged, and processed. Hit the link below for more olive oil buying tips.