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HOME CANNING THE BASICS

HOME CANNING THE BASICS . MARTHA SMITH PATNOAD, CP-FS CE FOOD SAFETY EDUCATION SPECIALIST DEPT OF NUTRITION AND FOOD SCIENCES UNIVERSITY OF RHODE ISLAND 401-874-2960 mpatnoad@uri.edu 8/10. Two Approved Methods of Canning Foods At Home. Boiling Water Canning (212 °F)

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HOME CANNING THE BASICS

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  1. HOME CANNINGTHE BASICS

  2. MARTHA SMITH PATNOAD, CP-FS CE FOOD SAFETY EDUCATION SPECIALIST DEPT OF NUTRITION AND FOOD SCIENCES UNIVERSITY OF RHODE ISLAND 401-874-2960 mpatnoad@uri.edu 8/10

  3. Two Approved Methods of Canning Foods At Home • Boiling Water Canning (212°F) Acid foods, ie- tomatoes, pickles, relishes, salsas, jams and jellies 2) Pressure Canning (at least 240°F) • Low acid foods • Mixtures of acid and low acid foods )

  4. Why Two Methods? • Depends upon the food item • Acid vs Low Acid

  5. Why Two Methods? Clostridium botulinum • Yeasts, molds and most bacteria are destroyed at boiling temperatures (212oF). • C. botulinum forms spores that require higher temperatures for destruction in a reasonable period of time (usually 240oF).

  6. Botulism Foodborne Illness • The botulinum toxin, one of deadliest known, causes botulism food poisoning. • 1 mg can kill 655 tons of mice. • Food can contain toxin without showing signs. • Antitoxin is available, but there is slow recovery. Permanent nerve damage is possible.

  7. Botulism Foodborne Illness • Symptoms usually appear within 12 to 72 hours: • Digestive upset (in some cases) • Blurred, double vision • Difficulty swallowing, speaking and breathing • Possible death from suffocation

  8. Botulism Poisoning • To germinate and produce toxin, the spores need the following conditions: • Anaerobic ( no air) • Low acid (pH > 4.6) • 40oF to 120oF • Relatively high moisture growth (multiplies) spore (germinates) bacterium waste materials and toxins

  9. Preventing Botulism • Home Canned Foods • Spores won’t germinate in acid foods (pH < 4.6). • Spores are killed when heated long enough at a specific temperature. • USDA usually recommends 240oF canned low-acid foods. • Pressure canner MUST be used for all low-acid foods.

  10. Preventing Botulism, cont. • Food must be properly prepared and processed for the correct time • Pressure canner accurate and operated correctly • Foods checked when opening jars • Foods should be boiled for at least 10 minutes before serving

  11. Preventing Botulism, cont. • Follow the recipe- NO MODIFICATIONS The following slow down heat penetration: • Extra sugar or fat • Oversize food pieces • Added thickeners • Use recommended canners Heat-up and cool-down times in pressure canners are counted toward “sterilizing” the contents of the jar. Don’t rush!!!

  12. HOME CANNING :THE PROCESSES

  13. Home Canning Basics FOODS CAN BE DIVIDED INTO TWO CATOGORIES: 1. ACID 2. LOW ACID

  14. Acid Foods • Generally all fruits • Tomatoes (specific amounts of citric acid or bottled lemon juice are added to acidify) • Sauerkraut • Foods to which large amounts of acid are added (pickles, relishes, salsas)

  15. Low Acid Foods • Generally all vegetables • Meats • Poultry • Seafood • Soups • Mixtures of acid and low acid foods (spaghetti sauce – meat, vegetables and tomatoes)

  16. Acidity Acidity measurement = pH Low pH values = high amount of acidity Bacteria can grow between pH 4.6 and pH 9.0 Bacteria grows best between pH 6.0 and pH 7.5 Vinegar 17

  17. Acidity Alkaline Acid 0 1.0 2.03.0 4.04.65.0 6.0 6.4 7.08.0 8.5 9.0 10.0 11.0 12.0 13.0 14.0 Distilled Water Egg White Commercial Mayonnaise Apples Orange Juice Chicken Milk Corn Soda Crackers Beef, Veal Pork Carrots, Pumpkins Sweet Potatoes Cheddar Cheese Limes Pickles Vinegar • Acidity levels affect bacterial growth • Different bacteria, different acid tolerance 18

  18. Home Canning Basics • Use only recipes/directions and DO NOT MODIFY from: USDA/ Cooperative Extension, National Center for Home Food Preservation (www.homefoodpreservation.com), Ball Blue Book, So Easy To Preserve. • Always use current methods and information. NEVER USE “granny’s method.” • Use only high/ quality food/ fresh produce. • Food must be properly prepared and processed the correct amount of time.

  19. Home Canning Basics • Food is placed in a canning jar with a 2-piece lid and is heated to a temperature that destroys microorganisms. • Pressure canner must be accurate and operated correctly. • Heat also inactivates enzymes that can cause changes in color, flavor and texture. • Air is driven from the jar during heating. • As the jar cools, a vacuum seal is formed.

  20. Home Canning Basics Processing Time * Each food has its own processing time. Follow directions carefully! * Time differs with size of jar. * Too Little • Spoilage

  21. How Canning Process Times Are Determined • Foods are prepared by a specific procedure. • The length of time it takes to adequately heat the coldest spot in the jar is determined. • Size of the jar, size of the food, consistency of the canning liquid, etc. all have an effect on how heat penetrates through the product.

  22. EQUIPMENT

  23. Jars and Lids • Wash canning jars; don’t use if nicked or scratched – keep hot until used • ALWAYS use new flat lids • Follow package instructions to prepare 2-piece lids and ring bands

  24. Home Canning Basics Vacuum Seal • Holds the lid on the jar. • Prevents recontamination of the food. • Prevents air from drying out the food.

  25. Testing for Seals • Listen for “pop” • Lid curved inward, won’t move when pressed * Clear ringing sound when tapped

  26. Packing Methods Raw/Cold Pack • Use fo foods that lose their shape when cooked • Raw food put into jars • Boiling hot liquid is poured over the food • Pack firmly, don’t crush

  27. Hot Pack • Preferred method for most foods. • Food is cooked in liquid before packing • Cooking liquid poured over food in jar • Fewer jars needed • Less floating • Better color and flavor • Easier to pack, foods pliable Note: If directions say only hot pack then hot pack!

  28. Headspace • Is the space in the jar between the inside of the lid and the top of the food or it’s liquid • Check directions for the correct headspace * Usually: • 1/4” jellied fruit products • 1/2” fruits, tomatoes and pickles • 1” to 1-1/4” low acid foods

  29. Headspace * Too little • Food may bubble out during processing • Deposit on rim may prevent sealing * Too much • Food at the top is likely to discolor. • Jar may not seal properly, as all the air may not be forced from jar during processing

  30. Pressure Canning

  31. Low Acid Foods pH greater than 4.6 • Meats • Poultry • Seafood • Generally all vegetables • Soups • Mixed canned foods (low acid + acid) • However, if pH < 4.6 = acidified foods

  32. Pressure Canners vs. Cookers • To be considered a pressure canner for USDA processes, the canner must be big enough to hold at least 4 quart-size jars • Pressure cookers/saucepans with smaller volume capacities are not recommended for use in canning • Enough heat may not be delivered during pressurizing and the cool-down period in smaller pressure cookers/saucepans

  33. Pressure Canner Features • Flat rack in bottom • Pressure regulator or indicator • Dial or weighted gauge • Vent pipe (port) for pressurizing • Safety valves or overpressure plugs • Safety locks when pressurized • Flexible gasket in lid

  34. Pressure Canners Features • Dial Gauge • Indicates pressure inside the canner • Must be checked for accuracy • Has dead- or counter-weight to close open vent for pressurizing • Pressure is increased or decreased by adjusting burner heat.

  35. Pressure Canners Features • Weighted Gauge • Regulates pressure inside the canner • Open vent is the same one that pressure regulator fits • Will continue to allow some air to be released from canner during process • Can’t be tested for accuracy

  36. Weighted Gauges cont’d • One piece • Fitting for 5, 10 or 15 pounds • Do not use dead- or counter-weight from dial gauge canner or pressure cooker. • Mirro: “jiggles” 3 to 4 times per minute. • Three piece • Number of pieces used determines 5, 10 or 15 pounds • Presto: rocks gently throughout entire process. • Mirro: “jiggles” 3 to 4 times per minute.

  37. Pressure CannerHow it Works • Steam inside the pressurized canner circulates around the jar • Transfers heat by conduction • Food in center of jar much reach 240°F

  38. Pressure Canner Processing • Use 1 inch headspace in jars. • A few products use 1-1/4” • Have 2” to 3” of water simmering or hot in canner. • Hot packed jars – simmering water, 180 F • Raw packed jars – warm to hot water, 140 F • Place jars on rack in canner. • Put lid on canner with weight off or petcock open.

  39. Venting the Canner • Also called “exhausting” the canner. • As the water boils in the canner, the “empty” space becomes a mixture of steam and air. • The temperature of a steam/air mixture is lower than the temperature of pure steam. • Venting eliminates (“exhausts”) the air so processing takes place in a pure steam environment. • Process times are intended only for a pure steam environment.

  40. Venting the Canner, cont. • Some manufacturers of weighted gauge canners say venting is not necessary. • USDA instructs to vent ALL pressure canners. • The one difference in “following manufacturer’s directions” if not included there. • Without proper venting, up to 30% of the sterilizing value of a 20-minute process may be lost. • At 10 pounds.

  41. Venting the Canner, cont. • Steam must flow freely from the open vent port in the lid for 10 minutes prior to pressurizing. • After putting filled jars in the pressure canner, fasten the lid in place. • Leave the ventport open. • Pipe where weighted gauge or dead weight will go. • Turn the heat on high. • When water boils, steam will start to come out of open vent. • Wait until there is a constant, strong funnel of steam, then start timing 10 minutes. • At the end of the 10 minutes, place weight in place to start the processing for the time sprecified in the directions.

  42. Loss of Pressure • Drop in pressure during processing means the sterilizing value of the process will be decreased. • Underprocessing. • Foodborne illness (botulism) and/or spoilage could result. • If pressure drops below target anytime during the process time, bring the canner back up to pressure and start timing the process over, from the beginning.

  43. Fluctuating Pressure • Large and/or quick variations in pressure during processing may cause loss of liquid from jars. • If the variation is a drop in pressure after process has begun, it also means the process must be started over.

  44. Opening the Pressure Canner • Turn off the heat at end of process and let jars cool in canner until pressure is 0 (Dial gauge should read zero) • Wait 10 minutes to remove the canner lid. • When the canner lid is opened, tilt it so the steam is pushed away from your face. • The steam, water and jars in the canner will still be very hot, even bubbling or boiling.

  45. Hot Water Bath Canning

  46. Tomato-Pepper Salsa

  47. Prepare the Canner • The canner must have a rack in the bottom • Fill the about half full of water, and begin heating • There must be enough water so the filled jars will be covered with 1 to 2 inches of water • The temperature should be about 180°F when it is time to add your filled jars

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