To ensure the olive oils you choose are in their prime, follow these guidelines:
Seek olive oil with the most recent "crush date." The product has an 18- to 24-month shelf life from that point. Although it won't be rancid when that shelf life passes, it also won't be at its peak of perfection.
If health is a priority, read labels carefully and take note of a product's levels of polythenols and oleic acid. Products that are labeled as olive oil but contain other compounds do not have the same health benefits. The higher the levels, the healthier the oil.
If you specifically want Italian oils, read carefully. A loophole in the country's labeling laws allows producers to label their products by where they are bottled, not where they are grown. So a company in Tuscany that imports oil from another country can sell it as Tuscan oil. Look for bottles labeled "produced and bottled by."
Know your olive oil types and base purchases on its use. Extra virgin olive oil, the first press, is additive-free and high-quality, but it loses its health benefits when exposed to heat and light. That's why some cooks recommend using another, less expensive form of oil for frying. You can judge a book by its cover, in this case. Or, more precisely, olive oil by its bottle. Clear glass bottles allow heat to disintegrate the oil. Good oils are packaged in darkened glass or plastic containers or in tin. Store olive oil in a shaded area.
Move beyond the Mediterranean. For example, Australia and South Africa are currently producing interesting oils.
Unwilling to spend the extra money? Try butter. Or make the oil you have last longer by using smaller amounts.