I got the lead to this article from Jennifer McLagan the author of the cookbook “Fat”. She is a strong believer in the use of animal fat for cooking. She says that most vegetable oils are rancid by the time they hit the stores’ shelves and so they are unhealthy, unlike fat from animals. Olive oil is the only one that is healthy but only when handled under certain condition which the article below describes.
Essential Oil by Mark Kurlansky, Bon Appetit, November 2008.
To read the whole article, click here.
Here’s a summary:
At times it seems that the search for good health has taken all the pleasure out of life. It has stripped us of butter, cream, marbled red meat, pork, and goose fat.
Olive oil, it often seems, is the only really good food we are still allowed.
So the news keeps getting better and better. It even turns out that the best-tasting (and least-tampered-with) olive oils are the most healthful.
This is the olive oil that the ancient Greeks and Romans rated the best and the most healthful. It's made from whole olives crushed at room temperature, which yields less oil than heating. And it's unfiltered…
Now for the bad news. Only the best olive oil, which is fairly rare and very expensive, has all the health benefits of the oil of ancient Greece. The well-informed consumer—who inspects labels and looks for the phrases "extra-virgin," "cold-pressed," and "first pressing"—may assume that a costly bottle with these three specifications is top-quality.
To label an oil "extra-virgin" in Europe, it must have less than 0.8 percent acidity. But the pressing process can yield an oil of higher acidity, in which case the oil is refined to reduce the acidity—but this also reduces the health benefits. Nowhere on the extra-virgin label does it indicate whether the oil has been refined.
Any contact with water is ruinous to olive oil from a health standpoint, because polyphenol antioxidants are water-soluble. The health-giving properties can literally be washed away.
Oxidation occurs over time, from exposure to heat and exposure to light, and the result is a substantially less healthful product.
Good olive oil can last two years or even longer before losing its healthful properties, but if antioxidants get washed away, its shelf life can be shortened to a few months. Most people will not realize when it has reached this turning point, and many oils (with the exception of those from deluxe Italian producers) are not labeled with a pressing or expiration date.
So what's the solution? There are not many guarantees in the olive oil world, but look for: (1) a fairly small bottle, since quality producers who try to sell the oil while young tend to sell it in small amounts; (2) a label that states not only "cold-pressed," "first pressing," and "extra-virgin," but also gives a date for this (make sure the date is within the past year); (3) a slight cloudiness to the oil, since clarity suggests filtration or other processes that diminish the quality; and (4) a dark-tinted bottle to prevent light damage.