Nuts : Safe Methods for Consumers to Handle , Store , and Enjoy Almonds , Chestnuts , Pecans , Pistachios , and Walnuts

SAFE HANDLING OF NUTS Bacteria are everywhere. Some types of bacteria are beneficial to human health, many have no impact on health, and some cause severe illness and even death. Dry foods like nuts are not a common source of harmful bacteria. However, in recent years a number of dried foods have been associated with outbreaks of salmonellosis. This has included outbreaks with raw almonds, cereal, peanut butter, dried pet food, black pepper, and sesame seeds. Refrigeration and freezing do not destroy this bacteria. The presence of harmful bacteria cannot be determined by sight, smell, taste, or texture. • including nuts in a diet low in saturated fat and cholesterol may help reduce the risk of heart disease • almonds, pecans, pistachios, and walnuts contribute to health through their protein, dietary fiber, and unsaturated fat


SAFE HANDLING OF NUTS
Bacteria are everywhere. Some types of bacteria are beneficial to human health, many have no impact on health, and some cause severe illness and even death. Dry foods like nuts are not a common source of harmful bacteria. However, in recent years a number of dried foods have been associated with outbreaks of salmonellosis. This has included outbreaks with raw almonds, cereal, peanut butter, dried pet food, black pepper, and sesame seeds. Refrigeration and freezing do not destroy this bacteria. The presence of harmful bacteria cannot be determined by sight, smell, taste, or texture.
• including nuts in a diet low in saturated fat and cholesterol may help reduce the risk of heart disease • almonds, pecans, pistachios, and walnuts contribute to health through their protein, dietary fiber, and unsaturated fat To enjoy nuts and get the most health benefits, nuts must be handled safely.
• Proper storage is necessary to keep the oil in nuts from going rancid. • Careful handling is needed to prevent nuts from being a source of harmful bacteria.  The length of time you can store nuts depends on  storage temperature and humidity (see table 1). Storage life is shorter at room temperature than in a refrigerator or freezer.

STORING NUTS
• Room temperature storage encourages insect growth (which may be important for backyard-harvested nuts) and causes nut oils to become rancid quicker. Nuts can maintain quality up to a few months at room temperature, with shorter time in a warmer environment. Rancid nuts are not unsafe Because of their association with two raw almond outbreaks, California almonds sold in retail stores must be treated in some way to eliminate Salmonella. Commercial blanching and roasting processes are examples. Almonds that are not roasted or blanched may be treated with a lighter steam or heat treatment or may be treated with the gas propylene oxide or other approved process. These lighter treatments are designed to eliminate Salmonella but retain the flavor and texture characteristics of a raw almond and retain the nuts' ability to germinate. The ability to germinate is considered important to some people. The health benefits, storage life, and flavor of nuts are not affected by these treatments. Almonds that are not obtained through regular market channels may not be pasteurized. Other nuts available at retail markets may also be treated to eliminate Salmonella.
If you grow your own nuts, see UC ANR Publication 8101 entitled Key Points of Control and Management for Microbial Food Safety: Edible Landscape Plants and Home Garden Produce for safety measures to use when harvesting tree nuts from the home orchard.
Follow good hygienic practices when shelling and eating nuts: but they have a sharp flavor that most people find unpleasant.
• Nuts retain quality for a year or more at refrigerator temperature (40°F [4°C] or below) or up to 2 years in the freezer (0°F [-18°C] or below).
• Shelled nuts absorb moisture and external flavors, so they should be packed in clean, moisture-free, and odor-tight packaging such as plastic or glass containers. If you want to store nuts obtained from a backyard orchard at room temperature, you will need to first freeze the nuts at 0°F (-18°C) for 48 hours to kill insect pests and their eggs and prevent them from destroying your harvest. Freezing the nuts is not necessary if you intend to store the nuts in the refrigerator. You can also use dry ice ( frozen carbon dioxide) to destroy insect pests prior to storage. For information on how to treat almonds with dry ice, see UC Cooperative Extension Publication 7184, Dry Ice: Easy Fumigation for Navel Orangeworm Control in Stored Almond Meats. These treatments do not destroy harmful bacteria such as Salmonella.
Nuts: Safe Methods for Consumers to Handle, Store, and Enjoy ANR Publication 8406 3 freezer temperature. Dried chestnuts will store longer than fresh chestnuts, but they lose both flavor and texture and will not roast properly. To rehydrate dried chestnuts, soak them in cold water for 3 or 4 hours before use.

NUTRITION AND HEALTH
Almonds, pecans, pistachios, and walnuts have high levels of unsaturated fatty acids. Extensive research on diet and health indicates that including these nuts in a diet low in saturated fat and cholesterol may protect against heart disease.

Storing Chestnuts
Guidelines for storing chestnuts are different from those for other nuts. Chestnuts are perishable, high-starch, lowfat foods more like potatoes or apples than tree nuts. Chestnuts lose moisture quickly at room temperature and humidity, causing the kernels to dry and harden. If stored at room temperature (above 50°F [10°C]), chestnuts usually mold within 2 weeks. Chestnuts will roast properly and taste fresh if you store them at 40°F (4°C) and at least 90 percent relative humidity within 1 or 2 days after harvest. Maintain proper moisture conditions by storing in-shell nuts in a plastic bag or closed plastic container in a refrigerator. You can store in-shell chestnuts for 1 month at refrigerator temperature of 40°F (4°C) or colder and for a year or more at freezer temperature of 0°F (-18°C) or colder. Shelled and dried chestnuts can be stored for a year or more at refrigerator or

NUTS GROWN IN CALIFORNIA
Nuts are the edible seed kernel of certain trees. Almonds, chestnuts, pecans, pistachios, and walnuts are all grown commercially in California. Following is a brief background about these California nuts. Nutritional value in the form of a Nutrition Facts label is listed for each nut. Except for chestnuts, nutritional value is given for one cup, with calories for one ounce at the bottom of each listing. Adjust for serving size when calculating the actual nutrients consumed.

FOOD ALLERGIES
About 8 percent of children and about 3 to 4 percent of adults in the United States are believed to have food allergies. A food allergy is a reaction of an individual's immune system to a food, usually a protein in the food. This protein is harmless to most people, but to the allergic individual it can cause a serious condition that should be diagnosed and treated by a boardcertified allergist. There are approximately 2,000 hospitalizations and 150 to 200 deaths each year due to food allergies.
Tree nuts are among the eight most common food allergens. Other common allergens include milk, eggs, peanuts, soy, wheat, fish, and crustacean shellfish. Allergic reactions can vary in severity and can include stomach and intestinal upset, skin irritations, sneezing, and shortness of breath. Some people experience a severe reaction called anaphylaxis. This is a life-threatening reaction that includes swelling of the throat, difficulty talking or breathing, vomiting, diarrhea, and/or a drop in blood pressure, which may result in unconsciousness.
If an individual says they are allergic to nuts, take care that they are not exposed through your cooking or meal preparation. Consider the following precautions: •

Almonds
People have enjoyed eating almonds for centuries. The almond tree is thought to have originated in China and Central Asia. Because of the nut' s popularity, the trees were planted in Europe. The almond tree thrived in the warm climate of Spain and Italy. The Spanish Franciscans brought almond trees to California in the mid-1700s. Initially, almond trees were planted in coastal areas, but they were not well suited to this cooler environment. In the 1800s, almond trees were planted in the warmer valleys. Research and cross breeding has developed the major almond varieties planted today.
California is the only place in North America where almonds are grown commercially. Today almonds are the most widely grown nut in California, with over 680,000 acres planted between Bakersfield and Red Bluff. In 2008 California produced over 1,630 million pounds of almonds, supplying 100 percent of the domestic supply and 70 percent of the world's crop.
Almonds are prized in many cultures as symbols of happiness and good fortune. Ancient Romans were said to give newlyweds almonds as a fertility charm. Jordan almonds (almonds with a hard candy coating) are often served at American weddings to represent happiness and good health. In a Swedish tradition, the diner who finds the almond hidden in a cinnamon-flavored rice pudding served at Christmas will have a year of good fortune.

Almonds
Photo: Courtesy of the Almond Board of California.
Photo: Courtesy of the Almond Board of California.
Jade almond stir fry. Commercial use of pistachios began in the 1930s, when Iranian businessmen started exporting pistachios to Europe and the United States. After World War II, export of pistachios to the United States increased until the beginning of the Islamic revolution in the 1970s. cultivated pecan trees. Spanish colonists planted more of the trees in the late 1600s. By the early 1800s, the English and French included pecans in their trade routes.
New Orleans became an important economic center for trading pecans. Nut varieties were improved when an African-American slave gardener from Louisiana, known only as Antoine, successfully grafted a superior wild pecan variety onto a seedling. The new variety was named "Centennial" because it won the Best Pecan Exhibit awarded at the Philadelphia Centennial Exposition in 1876. Mastering the grafting techniques led to the development of the variety of pecans grown today.
A pecan tree can reach a height of over one hundred feet and can live to be over one thousand years old. A pecan tree planted in George Washington' s Mount Vernon residence is said to have been a gift from Thomas Jefferson.
The United States produces about 80 percent of the world' s pecans. Over 3,100 acres of pecans are planted in California, with a production of 3.75 million pounds of nuts in 2008.

Raw Pistachios
Photo: Courtesy of USDA. Scientists believe that walnut trees have been The first pistachios were brought to California in the 1850s. In the 1930s, botanists focused on improving the nuts and adapting them to U.S. growing conditions. Interest in pistachios increased when trade with Iran halted after the American embassy incident in Teheran in 1976, the same year California harvested the first commercial crop. While Iran continues to lead in production, California is the second largest producer of pistachios worldwide with 118,000 acres planted and 278 million pounds harvested in 2008.
cultivated for at least 8,000 years. Walnuts are among the oldest fruitand nut-tree foods, with their origin likely to be in Persia. In the 16th and 17th century, physicians thought the appearance of food reflected the body part the food helped. Because the shells were round and the nut itself resembled the brain, eating walnuts was thought to increase brain power. The commercial walnut industry began in California in 1867 when an orchardist in Goleta (Santa Barbara County) planted English walnuts. Planted areas spread from Southern California to the central valley. While there are over 30 varieties of walnuts grown in California, the Chandler and Hartley variety account for about 60 percent of production.
China leads the world in quantity of nuts produced, followed by the United States, Iran, and Turkey. California produces 99 percent of the English walnuts in the United States, with Oregon, Washington, Pennsylvania, Michigan, Utah, Iowa,
Photo: Courtesy of the Mariani Nut Company.
Photo: Courtesy of the California Walnut Commission. The chestnut tree comes from a genus that contains eight or nine species of deciduous trees in the beech family. Chestnuts are native to temperate regions of the northern hemisphere. Chestnuts are often found in the market from September through December. They are frequently used during the winter holidays. Current worldwide chestnut production is about 500 million pounds, with China leading in production at 40 percent; followed by Korea, 15 percent; Italy, Turkey, and Japan, about 10 percent each; France, Spain and Greece, about 4 percent each; and the United States, Australia, New Zealand, Chile, and Argentina, at less than 1 percent each. Within the last 15 years, California has increased its planting of chestnuts to an estimated 600 acres, of which about half have trees in production.

Walnut-dusted baked apples and pears.
and Maine contributing to total production. In 2008, 223,000 acres of California walnut trees produced 872 million pounds of nuts.

Raw Chinese Chestnuts
Photo: Paul Vossen.

Chestnuts in tree.
Nuts: Safe Methods for Consumers to Handle, Store, and Enjoy ANR Publication 8406

ENJOYING NUTS
Nuts can be enjoyed in many ways: eaten out of hand, natural or roasted, tossed on salads or entrees, or included in breads, desserts, or candy. They also make great gifts. Check your local library for cookbooks or magazines with nut recipes. The following are Web sites with a selection of recipes or health information: