The Dangers of Vegetable Oil Extraction and Processing

An inside look at the nutritional and health problems associated with vegetable oil extraction and refining.

| November/December 1971

One very basic difference between our way of looking at vegetable oils and the industrial oil technician's viewpoint should be understood. When he sees dark color, it represents the presence of "impurities"—material that prevents the oil from being light colored, odorless and bland in taste. From our viewpoint, those "impurities" look desirable—the things which impart color, odor and flavor are NUTRIENTS. It is both tragic and ironic that the removal of nutrients should be equated with "purity". Tragic because if those nutrients were present they would contribute to the health of the consumer. Ironic because establishing the desired "purity" really results in producing poor quality food.

We qualified ourselves to make public observations about oils by conducting a threefold research program. First, we read from the following sources: The Encyclopedia Britannica;  "Rancidity in Oils" and "The Lowdown on Edible Oils" published by the Lee Foundation for Nutritional Research, Milwaukee, Wisconsin; and "The Story of Oils" published by Walnut Acres, Penns Creek, Pennsylvania. Second, we talked for several hours with Frank Lachle, a retired oil chemist with eminent technical qualifications who now owns Healthway Natural Foods, Watsonville, California. Third, we toured one of the largest vegetable oil extraction and refining plants in California, specializing in the production of safflower oil.

There are three methods of extracting vegetable oils from nuts, grains, beans, seeds or olives. The first is by use of a hydraulic press. This is an ancient method and yields the best quality oil. The only two materials that will yield enough oil without heating them first are sesame seeds and olives. Therefore, sesame oil and olive oil from a hydraulic press are the only oils which could truly be called "cold pressed". The terms "cold pressed" as applies to all oils and "virgin" as applies to olive oil are meaningless to the consumer. They have no legal definition, mean whatever the manufacturer wants them to mean, and do not give a true description of the product behind the label. Organic Merchants will not condone misleading labeling. The term "virgin" for olive oil will refer only to the first pressing by a hydraulic press without heat. The term "cold pressed" will refer only to hydraulic pressing without heat. These oils are the closest possible to the natural state, therefore have the most color, odor and flavor—in a word, the most NUTRITION—but they will often be unavailable because so little is produced this way.

If an Organic Merchant has an oil which has been extracted by hydraulic press but has been heated prior to pressing, he will refer to it as "pressed", not "cold pressed".

The second method is by expeller, described in "The Low down on Edible Oils" as follows: "This uses a screw or continuous press with a constantly rotating worm shaft. Cooked material goes into one end and is put under continuous pressure until discharged at the other end with oil squeezed out." Temperatures between 200 and 250 degrees are normal. Obviously, this type of extraction does not qualify as "cold pressed" either. Organic Merchants will refer to it as "expeller pressed."

Now with a hydraulically pressed oil labeled "cold pressed" or "pressed", you can assume you have a crude or unrefined of. But this is not true of "expeller pressed" oil because the common fate of expeller pressed oil is to be refined after extraction. So you need additional information with the words "expeller pressed". Organic Merchants will use either the word "crude" or "unrefined" to identify this additional classification of acceptable oils. 

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