H ome canning has changed greatly in the

Transcription

1 CANNING BASICS Leader s Guide This leader s guide is suggested food preservation information for new agents. It may also be used for county workshops. H ome canning has changed greatly in the last 200 years, but scientists have found ways to produce safer, higher quality products. The motivating factors behind home canning are better taste, economics, and selfsatisfaction. Using proper sanitation procedures and research-based recom-mendations can help these motivations become reality without the risk of foodborne illness. A series of publications has been compiled by the Kentucky Cooperative Extension Service. This series is an invaluable resource for persons who are canning for the first time or a source of updated information for experienced canners. 8 Principles of Home Canning HE Canning Fruits & Fruit Products HE Canning Tomatoes & Tomato Products HE & HE Canning Vegetables & Vegetable Products HE Canning Poultry, Red Meat & Fish HE Canning Fermented Foods & Pickled Vegetables HE Canning Jams & Jellies HE Principles of Home Canning (HE 3-325) Select good quality ingredients and foods. Foods should have no bruises, insectdamage, diseased spots, or mold. Clean, trim and wash food thoroughly. Wash hands, equipment, and work surfaces before any preparation begins. Use separate cutting boards for produce and meats. For peak quality, preserve foods within 6-12 hours of harvest. Apricots, nectarines, peaches, pears and plums should be ripened at least 1 day between harvest and canning. Chill and can fresh home slaughtered red meats and poultry immediately. Ice fish and seafood after harvest, eviscerate immediately and can within 2 days. Use research-based recipes for canning all foods low-acid and high-acid foods. Low-acid foods have ph values higher than 4.6 and include red meats, seafood, poultry, milk and all fresh vegetables. Process in a pressure canner. Acid foods have ph values of 4.6 or lower and include fruits, pickles, sauerkraut, jams, jellies, marmalades, fruit butters, and tomatoes acidified with lemon juice. Process in a boiling-water canner. Acid foods processed in boiling water should not be hot packed. Vegetables processed in a pressure canner are best raw packed. Know your altitude or elevation. All towns and communities in Kentucky are below 2,000 feet. The recipes in canning series are for use in Kentucky. Use jars designed for home canning and self-sealing lids. Sterilize jars for all jams, jellies, and pickled products processed less than ten minutes. To sterilize: 1. Place empty jars right side up on rack in boiling water canner. 2. Fill canner and jars with hot (not boiling) water to 1-inch above rims. 3. Boil for 10 minutes at altitudes less than 1,000 feet and 1 additional minute for each additional 1,000 feet elevation. 4. Remove and drain hot, sterilized jars one at a time. 5. Save hot water for processing filled jars. Empty jars used for vegetables, meats, and fruits to be processed in the pressure canner need not be sterilized before-hand. It is also unnecessary to sterilize jars for fruits, tomatoes, and pickled or fermented foods that will be processed ten minutes or longer in a boiling water canner.

2 Fill jars with hot food. Remove air bubbles with a plastic utensil. Wipe down the rims and sides. Adjust the headspace per recipe. Assemble lid by placing the sealing compound under metal lid next to jar rim. Tighten metal screw bands securely, but not too tight. Process acid foods in a boiling water canner for the correct time by filling the canner halfway with water. Preheat water to 140 F for hot-packed foods. Load jars into canner rack or fill canner, one jar at a time. Add more boiling water until water level is 1-2 inches above jar lids. Turn heat to highest position until water boils vigorously and set a timer for processing food. Cover canner and lower heat setting to maintain gentle boil. If needed, add more boiling water to keep water above jars. After boiling for recommended time, turn off heat and remove canner lid. Remove jars and place on towel. Leave 2 inches between jars to cool. Process low-acid foods in a weighted-gauge or dial-gauge pressure canner for the correct time by placing 2-3 inches of hot water in an approved canner. Place filled jars on rack. Fasten lid securely. Leave weight off vent port or open petcock. Heat at highest setting until steam flows from petcock or vent port. Maintain high heat setting and exhaust or vent steam 10 minutes. Place weight on vent port or close petcock. Canner should pressurize during next 3-5 minutes. Begin timing when weight starts to jiggle or rock, or when pressure gauge reads the correct pressure. Regulate heat for a steady rocking or jiggling motion or proper dial gauge pressure. Remove from heat. Do not force cool canner. After cooling, open vent port and wait 2 minutes. Open canner, lifting lid away from you. Cool jars slowly. Do not retighten jar lids. After hours, remove screw bands and test jar seals. Press the middle of the lid, checking no spring; tap the lid with a teaspoon for high-pitched, ringing sound; or hold jar at eye level and check for a concave surface. Store sealed jars in a cool dry place. CAUTION: Do not attempt to can pureed vegetables, red meats, or poultry meats, because proper processing times for pureed foods have not been determined for home use. Instead, can and store foods, then puree or blend them at serving time. Heat the blended foods to boiling, simmer for 10 minutes, cool and serve. Store unused portions in the refrigerator and use within 2 days for best quality. Suggested Activities: 1. Review Glossary of Terms. 2. Discuss annual testing: A gauge tester is available from National Presto Industries, Inc. Test Kitchen (715\ ). The cost is $45.00 and includes an annual check for accuracy. 3. Answer questions. Fruits & Fruit Products HE Select good quality fruits. Wash thoroughly. Peel and cut as needed. Dip cut fruit in mixture of 3 grams of ascorbic acid (1 teaspoon pure powdered ascorbic acid; six- 500 mg vitamin C tablets; or commercially prepared mix of ascorbic acid and citric acid) to 1 gallon of cold water to prevent browning. Lemon juice and water will also prevent browning. Syrups, from very light (10% sugar) to heavy (40% sugar) are used to retain flavor, color and shape. Syrups will not prevent spoilage. Select according to fruit, canner size and personal preference. Light corn syrups may replace up to one-half the table sugar called for in syrups. Either the raw or hot packed method may be used and processed in a boiling-water, dialgauge pressure or weighted gauge pressure canner. Follow directions carefully. In general, leave ½-inch headspace. Refrigerate fruit juice hours before canning. Pour off clear juice and strain through cheesecloth or coffee filter. Leave ¼- inch headspace. One quart of pie filling will fill an 8 or 9-inch pie. We recommend use of Clear Jel for proper consistency. Contact Kitchen Krafts at P.O. Box 805, Mt. Laurel, NJ , Leave a 1-inch headspace. Canning Basics FN-SSB.107LG Page 2 of 6

3 To can without sugar, select fully ripe but firm fruits of high quality. Prepare as for hot packs in HE Use water or regular unsweetened fruit juices instead of sugar syrup. It is best to use juice from fruit being canned. Add sugar substitutes only after serving. Tomatoes & Tomato Products HE and HE Select firm, disease-free tomatoes. Can green and yellow tomatoes as you would red tomatoes according to HE Tomatoes must be acidified regardless of the canning method used. To ensure acidity use one of the following: 1. Bottled lemon juice 1 tablespoon per pint or 2 tablespoons per quart. 2. Food grade citric acid ¼ teaspoon per pint or ½ teaspoon per quart. The designated amount of salt must be used for canning as the keeping quality will be affected if omitted. Use ½ teaspoon canning salt per pint or 1 teaspoon per quart. Pressure canners provide better quality with higher nutritive value. The hot pack method inactivates an enzyme that causes the separation of solid and liquid in cut or crushed tomatoes. To blanch tomatoes, dip washed tomatoes in boiling water for seconds or until skin splits. Dip in cold water slip off skins and remove cores. Leave tomatoes whole, cut in halves or crush. Tomato and tomato juice products require a ½-inch headspace. Vegetables & Vegetable Products HE Vegetable and vegetable products should be canned using the hot pack method in a dialgauge or weighted-gauge pressure canner (low-acid foods). Generally, a 1-inch headspace is recommended. There are no current USDA guidelines established for baby corn or mashed or pureed pieces of sweet potatoes, pumpkin, or winter squash. Do not substitute leafy greens, dried beans, cream-style corn, winter squash or sweet potatoes for the vegetables in mixed vegetable recipes. Poultry, Red Meat & Fish HE Choose freshly killed and dressed, healthy rabbits or chickens. Chill dressed chickens 6-12 hours before canning. Soak dressed rabbits 1 hour in salt water (1 tablespoon salt per quart) and rinse. Ground or chopped meat such as bear, beef, lamb, pork, sausage, veal or venison should be fresh and chilled. Strips, cubes or chunks of these meats should have excess fat removed. Soak strong-flavored wild meats for 1 hour in salt water. Follow the new guidelines for chile con carne and do not allow mixture to thicken before canning. Eviscerate fish such as blue, mackerel, salmon, steelhead, trout and other fatty fish except tuna within 2 hours after harvest. Keep cleaned fish on ice until ready to can. Follow canning procedures for smoked fish to the letter. Glass-like crystals of magnesium ammonium phosphate sometimes form in canned salmon or tuna. There is no way for the home canner to prevent the formation. The crystals usually dissolve when heated and are safe to eat. Canning Basics FN-SSB.107LG Page 3 of 6

4 Fermented Foods & Pickled Vegetables HE In May, 1994, USDA withdrew the recommendations for Refrigerator Dills, Whole Pack until further notice. The current guidelines may be inadequate for the inactivation of Listeria bacteria. Select fresh, firm fruits or vegetables free of spoilage. Do not use waxed cucumbers as brine will not penetrate the wax. Choose cucumbers about 1½ inches in length for gherkins and about 4 inches long for dills. Choose odd shaped and more mature cucumbers for relishes and bread and butterstyle pickles. Remove and discard a small slice from the blossom end of fresh cucumbers as they may contain an enzyme which causes excessive softening of pickles. Measure or weigh amounts carefully as flavor and safety may be affected. Use of canning or pickling salt is recommended. Fermented and nonfermented pickles may be safely made using either iodized or noniodized table salt. However, non-caking materials added to table salts may make the brine cloudy. Flake salt varies in density and is not recommended for use. Use of reduced sodium salt in fermented pickle recipes is not recommended. Sauerkraut and brine pickles MUST have the amount of salt called for in the recipe. Salt is vital to microbial safety and texture. Use white distilled and cider vinegars of 5% acidity (50 grain). Do not use home-made vinegars. Reduced sodium salts may be used in quick pickle recipes but may give a slightly different taste than expected. The calcium in food-grade lime improves pickle firmness. Remove excess lime to ensure safety by repeatedly rinsing (a total of 4 times) and use only when recipe indicates. It is difficult to find food-grade lime. Use a 1-gallon container for each 5 pounds of fresh vegetables. Use food grade plastic and glass containers as substitutes for stone crocks. Do not use garbage bags or trash liners. Suggested Activity: Process either Pickled Dilled Beans, Pickled Corn Relish, Reduced-Sodium Sliced Dill Pickles, or Reduced-Sodium Sliced Sweet Pickles. Jams & Jellies HE Refer to the fact sheet, The Science of Jams and Jellies. Remake instructions are listed in HE or follow the commercial pectin instructions. Suggested Activity: Pear-Apple Jam (made with added pectin) and/or Refrigerated Grape Spread (reduced-sugar fruit spread). Canning Basics FN-SSB.107LG Page 4 of 6

5 Glossary of Terms Acid foods contain enough acid to result is a ph of 4.6 or lower. Includes all fruits except figs; most tomatoes; fermented and pickled vegetables; relishes; and jams, jellies and marmalades. Acid foods may be processed in boiling water. Altitude refers to the vertical elevation of a location above sea level. Ascorbic acid is the chemical name for vitamin C. Lemon juice contains large quantities of ascorbic acid and is commonly used to prevent browning of peeled, light-colored fruits and vegetables. Bacteria is a large group of one-celled microorganisms widely distributed in nature. A blancher is a 6 to 8-quart pot with a lid designed with a fitted perforated basket to hold foods in boiling water or with a fitted rack to steam foods. A blancher is useful for loosening skins on fruits to be peeled or for heating foods to be hot packed. A boiling water canner is a large standard size kettle with a lid and jar rack, designed for heat processing 7 quarts or 8 to 9 pints in boiling water. Botulism is an illness caused by eating the toxin produced by growth of Clostridium botulinum bacteria. C. botulinum grow in moist, low-acid foods containing less than 2% oxygen and stored between 40 and 120 F. Proper heat processing destroys this bacterium in canned food. Freezer temperatures inhibit its growth in frozen food. Low moisture controls growth in dried foods. High oxygen controls growth in fresh foods. Canning is a method of preserving food in airtight, vacuum-sealed containers with sufficient heat processing to allow the storage of canned foods at normal home temperatures. without the anticaking or iodine additives. Citric acid is a form of acid that can be added to canned food. It increases the acidity of low-acid foods and may improve the flavor and color. Enzymes are proteins in food which accelerate many flavor, color, texture and nutritional changes, especially when food is cut, sliced, crushed, brushed, or exposed to air. Proper blanching or hot pack methods destroy enzymes and improve food quality. Exhausting is the removal of air from within and around food from jars and canners. Blanching exhausts air from live food tissues. Exhausting or venting of pressure canners is necessary to prevent a risk of botulism in lowacid canned foods. Fermentation changes the natural sugars in a food to lactic acid by the intentional growth of bacteria, yeast or mold. Lactic acid is a major flavoring and preservative agent in sauerkraut and in naturally fermented dills. Alcohol, vinegar and come dairy products are also fermented foods. Headspace is the unfilled space above food or liquid in jars. The headspace allows for food expansion as jars are heated and for forming vacuums as jars cool. Heat processing is a treatment of food in jars with sufficient heat to enable storing food at normal home temperatures. A hermetic seal is an airtight seal which prevents reentry of air or microorganisms into packaged foods. Hot pack is a method of heating raw food in boiling water or steam and filling jars with the food while the food is hot. Canning salt or pickling salt is regular table salt Canning Basics FN-SSB.107LG Page 5 of 6

6 Low-acid foods contain very little acid and have a ph above 4.6. The acidity in these foods is insufficient to prevent the growth of bacterium Clostridium botulinum. Vegetables, some tomatoes, figs, all meats, fish, seafood, and some dairy foods are low acid. To control all risks of botulism, jars of these foods must be heat processed in a pressure canner, or tomatoes may be acidified to a ph of 4.6 or lower before processing in boiling water bath. Microorganisms include bacteria, yeast, and mold. When microorganisms are placed alive in a suitable environment, they grow rapidly and may divide or reproduce every 10 to 30 minutes. Undesirable or pathogenic microorganisms cause disease and food spoilage. Microorganisms are sometimes intentionally added to ferment foods. Mold is a fungus-type microorganism whose growth on food is usually visible and colorful. Molds may grow on many foods, including acid foods like jams and jellies and canned fruits. Recommended heat processing and sealing processes prevent their growth jams and jellies. Mycotoxins are toxins produced by the growth of some molds on foods. Open-kettle canning is a non-recommended canning method. Foods canned using this process are not adequately heat processed to pull a vacuum within the jar. Food canned using this process often spoil because they become recontaminated while the jars are being filled. Pasteurization is a heat process that destroys the most heat-resistant pathogenic or disease-causing microorganism known to be associated with that certain foods. ph is a measure of acidity or alkalinity. Values range from 0 to 14. A food is neutral when its ph is 7.0. Lower values are increasingly more acid; higher values are increasing more alkaline. Pickling is the practice of adding enough vinegar or lemon juice to a low-acid food to lower its ph to 4.6 or lower. Properly pickled foods may be safely heat processed in boiling water. A pressure canner is a specifically designed metal kettle with a lockable lid used for heat processing low-acid food. These canners have jar racks, one or more safety devices, systems for exhausting air and a way to measure or control pressure. Raw pack or cold pack refers to a canning procedure in which jars are filled with raw, unheated food. It is acceptable for canning lowacid foods, but allows more rapid quality losses in acid foods heat processed in boiling water. A spice bag is a closeable fabric bag used to extract spice flavors in a pickling solution. Style of pack refers to the form of canned food, such as whole, sliced, pieces, juice or sauce. The term may also be used to reveal whether food is filled raw or hot into jars. A state of negative pressure is referred to as pulling a vacuum. The higher the vacuum in a jar of processed food, the less air left in the jar. Yeast is a group of microorganisms which reproduce by budding. They are used in fermenting some foods and in leavening breads. However, foods with yeast growth should be discarded. Sandra Bastin, Ph.D., R.D, Food & Nutrition Specialist Educational programs of the Kentucky Cooperative Extension Service serve all people regardless of race, color, age, sex, religion, disability, or national origin. Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, C. Oran Little, Director of Cooperative Extension Service, University of Kentucky College of Agriculture, Lexington, and Kentucky State University, Frankfort. Selected publications are also available on the World Wide Web at Issued ; FN-SSB.107LG Canning Basics FN-SSB.107LG Page 6 of 6