There is probably no other single factor more responsible for the degradation of olive oil than improper packaging and storage. Olive oil is highly perishable and breaks down when exposed to ultra violet light. Never store olive oil in clear plastic or glass containers for a prolonged period of time. In addition, olive oil oxidizes when exposed to air. The larger the surface area exposure the more rapid oxidation occurs. Once an olive oil container is opened the natural breakdown and increase in peroxide values is accelerated, creating rancid oil.