First, check whether sunflower seed oil has a special smell. If the taste is normal and there is no pungent smell, then this oil is edible in theory if it is properly preserved. Usually, the shelf life of food is fixed. As long as it is properly stored and does not deteriorate, sunflower seed oil before opening can still be safely eaten after two years of expiration. However, once opened, the shelf life of edible oil will be shortened, because air, light and microorganisms may lead to oxidative deterioration of oil. Therefore, although the oil before opening may look and smell normal, in order to ensure safety, it is best to eat it within a certain period of time after opening, and pay attention to the storage conditions of the oil.