The human body requires the intake of six types of substances for survival: Fats, carbohydrates, proteins, water, vitamins, and minerals. Certain fatty acids are essential to our health and fats and oils are important components of our food and their preparation. Fat is responsible for much of the texture, appearance, and taste of our baked goods. Since fat is both required for human health and an important part of our diets, we should include fat in our emergency preparedness plans–some combination of butter, margarine, vegetable oil, olive oil, and shortening. (Oils are liquid at room temperature; fats are solid.) Though we need to store these foods to maintain our lifestyles and our health, they represent a particular food storage challenge. As oils and fats age, they oxidize. Oxidation is the process that turns fats rancid. Rancid foods not only taste bad, they are unhealthy. As fats and oils breakdown, they become toxic. These oxidized oils promote arterial damage, cancer, inflammation, degenerative diseases, and premature aging.1 So it is important that we store fats properly, use all fatty foods well before they become rancid, and discard those foods that have been stored too long.
So what is the proper way to store fats and oils? Three conditions accelerate the oxidation of fats: the exposure to heat, to oxygen, and to light. Fats should be stored in cool or cold conditions-never in a warm pantry-in the dark, and sealed so that they are not exposed to air. We store our vegetable oil, olive oil, and shortening in a dark, fifty-degree room. Once opened, we store our vegetable and olive oils in the refrigerator.
How long can we safely store fats and oils? That, of course, depends on the storage conditions. At seventy degrees, shortening can be kept for eight months.2 Butter does not last long at all in the refrigerator-only two weeks-but can be stored for up to nine months in the freezer (not the freezing compartment of a refrigerator which is usually not as cold).3 Margarine can also be frozen though some margarine tends to be flaky once thawed. While I do not have a government source for the shelf life of vegetable oils, I would not store oils for over eight to ten months.4 My recommendation is to store butter in the freezer for up to nine months and store oils and shortening for eight months at seventy degrees–slightly longer at cooler temperatures. Maybe more so than any other food group, fatty foods must be carefully and conscientiously rotated to maintain adequate and healthy stocks. Use what you store and store what you use.
Not just oils and fats have to be carefully stored. Any food with a significant fat content such as nuts, cookies, or whole wheat flour is subject to rancidity. Nuts should be stored in a cool, dark environment and always checked for rancidity before they are used. Ideally, nuts should be stored in metal or metalized containers-plastic bags are permeable to air and slowly allow oxygen to seep into the package and accelerate oxidation. We keep our nuts in the freezer-even unopened bags. Freshly ground whole wheat should be kept in the refrigerator and used within two weeks. (The commercial milling process removes most of the fat from wheat. Most white flour is nearly fat free. Any whole wheat flour with a fat content higher than two percent should not be stored.) Any food that has any rancid odor should be discarded.
So what fats should we store? Flaxseed oil and safflower oil oxidize very rapidly and are not good candidates for storage. Most commonly purchased vegetable oils are extracted with heat, pressure, and chemical additives, which may accelerate oxidation.5 Cold pressed oils are better though more expensive. I know of no government source for the shelf life of cold pressed oils. Check any oil carefully for rancidity before using.
The modern diet is high in the consumption of Omega-6 essential fatty acids and low in Omega-3 fatty acids. Flesh from grain and corn fed animals and most vegetable oils are high in Omega-6. The National Institutes of Health urges nearly all people to reduce the consumption of the Omega-6 fatty acids and increase the consumption of Omega-3 believing that this is critical to achieving optimal brain and cardiovascular functions.6 Of the commonly used oils, canola oil and soybean oil contain Omega-3 fatty acids. Avocados and nutmeats, especially walnuts, are high in Omega-3.7
Andrew Weil in his excellent book, Eating Well for Optimum Health, promotes olive oil as a healthy substitute for vegetable oils. It has the highest percentage (77%) of monounsaturated fats of any of the oils but is low in Omega-3. There are many different varieties of olive oil available, each with a little different flavor. Choose what you like but watch it carefully for rancidity. Stored in the refrigerator or a cool basement, olive oil may turn cloudy-but the quality is unaffected.
Nutritionists advise us to reduce our intake of hydrogenated fats-margarine and shortening. Margarine is not a healthy substitute for butter.8 Hydrogenated means that hydrogen atoms have been added to stabilize the oil and turn it from a liquid at room temperature to a solid. A saturated fat is a fat that has been saturated with hydrogen atoms, is stable and less prone to oxidation but the molecular composition of saturated fats is believed to raise serum cholesterol levels.9
Store oils and fats-they are essential to a well-prepared household and some fat is necessary to maintain health. However, choose the right fats and oils, store them properly, rotate religiously, and discard any that happen to get old.
Prepared by Dennis Weaver, January 15, 2003
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1Weil, Andrew, M.D., Eating Well for Optimum Health, The Essential Guide to Food, Diet, and Nutrition, Alfred A. Knopf, New York, 2000, p.89, and:
Amendola, Joseph and Rees, Nicole, Understanding Baking: The Art and Science of Baking, Third Edition, John Wiley and Sons, Inc. Hoboken, New Jersey, 2003, p. 84.
2Kansas State University, “Cupboard Storage Chart” www.oznet.ksu.edu/dp_fnut/hrap/storage, Sept. 9, 2002.
3Clemson University, http://hgic.clemson.edu/factsheets, Nov. 11, 2002.
4Salsbury, Barbara G., Just in Case: A Manual for Home Preparedness, Bookcraft, Salt Lake City, 1975, p. 158. This source states that oils can be kept for six to twelve months depending on storage conditions. The author believes this is accurate.
5Weil, Ibid., p. 91. In addition to accelerating oxidation, common extraction methods may create detrimental trans -fatty acids.
6Ibid., p. 88.
7Ibid., p. 95.
8Ibid., p. 93.
9Amendola and Rees, Ibid., p. 83.